MPC Expansion previews bug

When creating new expansions, file extensions in the [Previews] folder must match the case of the corresponding Program file. If the extensions are a different case, they will not preview on the hardware. This seems to be a new bug introduced in 2.8? I haven't experienced this issue in previous versions and have had to correct this with most of my custom expansions and a few purchased expansions.

Example:
\Bass.XPM with \[Previews]\Bass.XPM.wav works properly
\Bass.XPM with \[Previews]\Bass.xpm.wav does not work

Lowercase .xpm file extension is the default when the program is created and saved by the MPC, I think you'd have to be purposely adding that uppercase .XPM at some point. In standalone there's no option to add your own file extension, it's just added automatically. In the MPC Software the MPC doesn't allow me to save it if I change it to uppercase ('invalid file name'). Did you add this in your computer's file explorer/finder?

Are you on a Mac? Depends on disk formatting whether upper case is regarded or not.

...have the same issue..using upper and or lower case..didn't help....
...this is somewhat annoying.... is there any information about it in detail?
some xpm just don't preview for me...very weird