I've been using this for years but recently I've found I cannot re-save existing excel files on google drive encrypted folders.

I'm using a GSuite account with Google Drive for desktop 48.0.13.0 on Windows 10 Pro 21H1

Steps:

I open an existing excel file. e.g. X:\Google Drive File Stream\My Drive_Privat\2021\Inversions\20210601 Seleccion.xlsx
I do some changes and when I try to save it I receive the following message:

Microsoft Excel is unable to access the file 'X:\Google Drive File Stream\My Drive_Privat\2021\Inversions\074D6000'. There can be several reasons:

The file name or path does not exist.
Another program is using the file
The book you are trying to save has the same name as another book that is currently open.

In fact the file name '074D6000' has been randomly generated while saving. It's not the one I opened. The folder is the correct one.
If I check the folder I can see en empty file called '074D6000' (0 Kb, no extension).
If I try to delete this empty file and save again from excel then it simply generates another random name and still I cannot save.
If I try to "save as..." with a different name on the same folder I get the same error (with another random name).
If I try to "save as..." on a different folder, e.g. the upper folder (still encrypted), I get the error.

This location on the X: disk is full.
Choose another location and try again.

The Google Drive File Strem has at least 400Gb available.
If I copy using the explorer another file from a local drive to the same encrypted folder I can save it without problems (so the X: drive is not full and it's writeable).

Only solution I found is to "save as" into a local drive (or into the same I: Google Drive but on an unencrypted folder) and then copy the file on the proper encrypted folder but this is unmaintainable as I end up with multiple copies of the same file that I manually have to move to the proper folder with a high risk of forgotting to move or to edit an older version.

This was an example but it happens with every excel file I'm using, no matter which folder or if the file is recent or it was created months ago.