Illustrator files saved on Windows lose their preview thumbnail when changing extension to .ait

To prevent accidentally saving over common library files (stock graphics and the like) we save our artwork files as .ai, then change the extension to .ait so that they will open as an untitled file. There are a couple of reasons I do things this way instead of saving them as .ait files from the get go.

• The main reason is that it's not uncommon that I'll need to run a batch script on several files. As part of that batch, I open the file, make some change(s), then save the file. If the files are initially saved as a template file, they will always open as "Untitled" documents and as such, the user will see a Save As dialog for each document that is batched. If the files are initially saved as ai, then you can always interchange the extensions to get the desired behavior.
• The auxiliary reason is that if you save an .ait file, no preview/thumbnail is saved with it. But if you save it as .ai first, then batch rename the extensions to .ait, the file retains preview information, but it still opens as untitled like we want.

So that's the workflow and the rationale behind it. However, with the remote working situation, we've encountered issues that we didn't see in the office when everyone was using Mac.

When a file is saved on a windows machine, the preview/thumbnail goes away after changing the extension to .ait (regardless of the environment in which the extension is changed). As far as I can tell, the save settings (in the save as dialog) are identical in both operating systems, yet the behavior of the saved files is different. The issue exists in all versions of release 24 that i've tested so far..

Has anyone else noticed this issue, or know what can be done about it?

{Renamed by MOD}