I would contact firstname.lastname@example.org to get their advice.
But if you want to try something now…
So to just double check:
- The physical location in Google folders is the same?
- The Google sheet shows the same path info to the file?
- The two files are in the same column on the same sheet?
- The issue appears in the editor, the device, both?
For the editor, the only thing I can suggest is to close AppSheet and clear Browsing data - make sure you have the “Cached images and files” option checked. This may take a while if you have a lot of cached items. Wait for it to finish. Once done, reopen and retry. The idea is to make sure the cache is completely cleared forcing AppSheet to reload the images.
For a device, its the same process. Close the app then go into settings and clear browsing data and history. Reopen and retry.
If none of this works, which I don’t think should be necessary in the first place, then contacting AppSheet is your best options.