diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8b07d9b55..ebebe5634 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -43,11 +43,14 @@ _Breaking developer changes, which may affect downstream projects or sites that
 * Fix bug which made it impossible to change an object's preset from a sub-preset to the respective parents preset (e.g. from Driveway to Service Road) ([#9372])
 #### :hourglass: Performance
 #### :rocket: Presets
+* Clamp degree values in `direction` fields between 0 and 359 degrees ([#9386])
+* Disable increment/decrement buttons on number fields if the input value is not numeric or when there is a multi-selection with conflicting values
 #### :hammer: Development
 * Upgrade to Transifex API v3 ([#9375])
 
 [#9372]: https://github.com/openstreetmap/iD/issues/9372
 [#9375]: https://github.com/openstreetmap/iD/pull/9375
+[#9386]: https://github.com/openstreetmap/iD/issues/9386
 
 
 # 2.23.2
diff --git a/modules/actions/reverse.js b/modules/actions/reverse.js
index 31f498f03..163660ea4 100644
--- a/modules/actions/reverse.js
+++ b/modules/actions/reverse.js
@@ -99,17 +99,19 @@ export function actionReverse(entityID, options) {
             return onewayReplacements[value] || value;
 
         } else if (includeAbsolute && directionKey.test(key)) {
-            if (compassReplacements[value]) return compassReplacements[value];
+            return value.split(';').map(value => {
+                if (compassReplacements[value]) return compassReplacements[value];
 
-            var degrees = parseFloat(value);
-            if (typeof degrees === 'number' && !isNaN(degrees)) {
-                if (degrees < 180) {
-                    degrees += 180;
-                } else {
-                    degrees -= 180;
+                var degrees = Number(value);
+                if (isFinite(degrees)) {
+                    if (degrees < 180) {
+                        degrees += 180;
+                    } else {
+                        degrees -= 180;
+                    }
+                    return degrees.toString();
                 }
-                return degrees.toString();
-            }
+            }).join(';');
         }
 
         return valueReplacements[value] || value;
diff --git a/modules/ui/fields/input.js b/modules/ui/fields/input.js
index 76b795d32..db55fa600 100644
--- a/modules/ui/fields/input.js
+++ b/modules/ui/fields/input.js
@@ -28,6 +28,7 @@ export function uiFieldText(field, context) {
     var _entityIDs = [];
     var _tags;
     var _phoneFormats = {};
+    const isDirectionField = field.key.split(':').some(keyPart => keyPart === 'direction');
 
     if (field.type === 'tel') {
         fileFetcher.get('phone_formats')
@@ -112,23 +113,43 @@ export function uiFieldText(field, context) {
                     var which = (d > 0 ? 'increment' : 'decrement');
                     return 'form-field-button ' + which;
                 })
-                .attr('title', function(d){
+                .attr('title', function(d) {
                     var which = (d > 0 ? 'increment' : 'decrement');
                     return t(`inspector.${which}`);
                 })
                 .merge(buttons)
                 .on('click', function(d3_event, d) {
                     d3_event.preventDefault();
+
+                    // do nothing if this is a multi-selection with mixed values
+                    var isMixed = Array.isArray(_tags[field.key]);
+                    if (isMixed) return;
+
                     var raw_vals = input.node().value || '0';
                     var vals = raw_vals.split(';');
                     vals = vals.map(function(v) {
-                        var num = parseFloat(v.trim(), 10);
-                        if (isFinite(num)) return clamped(num + d);
+                        var num = Number(v);
+                        if (isDirectionField) {
+                            const compassDir = cardinal[v.trim().toLowerCase()];
+                            if (compassDir !== undefined) {
+                                num = compassDir;
+                            }
+                        }
 
-                        const compassDir = cardinal[v.trim().toLowerCase()];
-                        if (compassDir !== undefined) return clamped(compassDir + d);
+                        if (!isFinite(num)) {
+                            // do nothing if the value is neither a number, nor a cardinal direction
+                            return v.trim();
+                        }
 
-                        return v.trim(); // do nothing if the value is neither a number, nor a cardinal direction
+                        num += d;
+                        // clamp to 0..359 degree range if it's a direction field
+                        // https://github.com/openstreetmap/iD/issues/9386
+                        if (isDirectionField) {
+                            num = ((num % 360) + 360) % 360;
+                        }
+                        // make sure no extra decimals are introduced
+                        const numDecimals = v.includes('.') ? v.split('.')[1].length : 0;
+                        return clamped(num).toFixed(numDecimals);
                     });
                     input.node().value = vals.join(';');
                     change()();
@@ -294,7 +315,7 @@ export function uiFieldText(field, context) {
                 if (field.type === 'number' && val) {
                     var vals = val.split(';');
                     vals = vals.map(function(v) {
-                        var num = parseFloat(v.trim(), 10);
+                        var num = Number(v);
                         return isFinite(num) ? clamped(num) : v.trim();
                     });
                     val = vals.join(';');
@@ -324,6 +345,18 @@ export function uiFieldText(field, context) {
             .attr('placeholder', isMixed ? t('inspector.multiple_values') : (field.placeholder() || t('inspector.unknown')))
             .classed('mixed', isMixed);
 
+        if (field.type === 'number') {
+            const buttons = wrap.selectAll('.increment, .decrement');
+            if (isMixed) {
+                buttons.attr('disabled', 'disabled').classed('disabled', true);
+            } else {
+                var raw_vals = tags[field.key] || '0';
+                const canIncDec = raw_vals.split(';').some(val => isFinite(Number(val))
+                        || isDirectionField && cardinal[val.trim().toLowerCase()]);
+                buttons.attr('disabled', canIncDec ? null : 'disabled').classed('disabled', !canIncDec);
+            }
+        }
+
         if (field.type === 'tel') updatePhonePlaceholder();
 
         if (field.key.split(':').includes('colour')) updateColourPreview();