Same file contents same extension made by 2 different apps 1 file contents visible the other not visible

[themelz]

I use Visual Studio Code to create files with the extension hx. Before upgrading to macOS Big Sur, QLStephen easily displayed any of those files. After Big Sur, none would. Tried all the things I could find online, nothing worked.

But I did find that if I edited the file with a different app (BBEdit) and saving with the same hx extension, all of a sudden QLStephen could display the contents. I noticed that I could drag an VSC created hx file to BBEdit and it would open. But if I tried the open dialog in BBEdit, the file would be grayed out and not eelectable. But after saving it with BBEdit, it was selectable in the open dialog.

Stranger to me is that once QLStephen can display an hx file, if I edit and save that file with VSC, QLStephen can still display it.

I have attached 3 small test files in a zip file. Test1.hx was created with VSC and QLStephen does not display it. In Finder I made a duplicate named Test2.hx, QLStephen still couldn't display it. Opened that with BBEdit, deleted then reinserted a char, saved it with BBEdit and QLStephen displayed it. In Finder made a copy of that called Test3.hx. With VSC, I opened and edited that then saved it and QLStephen still could display it. The contents of all three hx files are identical.

Any ideas of what is causing this? And no there are way too many hx files for me to load into BBEdit and resave!
Test.zip