‘Png’ disables ‘as a copy’ override for images 256+; not for images at 128.+?

Issue:  The Photoshop Elements application does not consitently allow overriding the current .Png file types, when saving changes.  Depending on file size loaded or manipulation of other parameters, while editing a photo, the use of 'as a copy' override is disabled in error.
 
Details: Open up ‘png’ files for editing. Resize the image files; for example, 513x234 is 512x512 for canvas size. When saving file, the file comes up with the ‘Photoshop’ option enabled automatically for 256+ image file sizes. Changing to the ‘png’ format disables the ‘as a copy’ checkbox; thereby, forcing the image to save as a copy in the description. However, if the same sequence of events are used for an image file at 128+ size, the ‘Photoshop’ file format is not picked automatically. And the ‘as a copy’ is allowed to be disabled - this is expected behavior, allowing the image to override the original ‘png’ file. To sum up the error - the ‘Photoshop’ automatic file type selection, erroneously disables the ability to override the original ‘png’ file formats.
 
Note: Also notice changing more than one parameter seems to trigger the bug. For example, changing width and height in the same trsansaction.  (See Attached Video)