Update date/time cmpnts to reset any chnages they made on umount. Update schedule date/time cmpnt to clear release time when selecting anytime option.

ui/component/publishForm/view.jsx

@@ -569,13 +569,6 @@ function PublishForm(props: Props) {
     setShowSchedulingOptions(isLivestreamMode && fileSelectSource === SOURCE_NONE);
   }, [isLivestreamMode, fileSelectSource]);
 
-  // Reset any set release time if switching to live stream mode.
-  useEffect(() => {
-    if (mode === PUBLISH_MODES.LIVESTREAM) {
-      updatePublishForm({ releaseTimeEdited: undefined });
-    }
-  }, [mode, updatePublishForm]);
-
   if (publishing) {
     return (
       <div className="main--empty">

ui/component/publishReleaseDate/view.jsx

@@ -1,5 +1,5 @@
 // @flow
-import React from 'react';
+import React, { useEffect } from 'react';
 import Button from 'component/button';
 import DateTimePicker from 'react-datetime-picker';
 
@@ -86,6 +86,12 @@ const PublishReleaseDate = (props: Props) => {
     }
   }
 
+  useEffect(() => {
+    return () => {
+      updatePublishForm({ releaseTimeEdited: undefined });
+    };
+  }, []);
+
   return (
     <div className="form-field-date-picker">
       <label>{__('Release date')}</label>