As a Mac user, I'm thinking Pixelmator Pro could be a good choice for editing images. However, I'm discovering EXIF issues that do cause problems. For example, PM Plus fails to recognise the altered GPS data.
If this is a Pixelmator problem I would like to help them fix it. If the problem is with PM Plus, then I think you should know. Either way, I seek you assistance and am happy to send both images by WeTransfer for closer inspection.
Screenshots of the EXIF BEFORE and AFTER round-tripping.