
Hello,
I appreciate you posting this concern to Microsoft Community Forum.
As per your description, it sounds like Excel on Android is saving files in an inaccessible location, preventing proper syncing.
First, check where Excel is saving your files. When saving, tap File > Save As, then select a clear storage location like OneDrive or a specific folder on your device. Avoid saving to "This Device," as it may store files in a temporary location. You can find more details on saving files in Office on Android here, Saving files in Office on Android phones - Microsoft Support
To prevent this issue in the future, ensure AutoSave is enabled when working with cloud storage. If Excel continues saving files incorrectly, consider reinstalling the app or clearing its cache to reset its behavior.
Hope this information will help in resolving the issue.
Regards,
Matt | Microsoft Community Moderator