Merge FX always coming back

Hi folks,

I just updated my MacBook to Big Sur and RB 6.5.

Just realized that whenever I start the RB app, it automatically creates the "MERGE FX" folder with 18 wav files. And they are also automatically imported into my collection. 
Of course I can delete them from the hard drive and from my collection. But they will come back again and again. 
As I use RB only to manage my files and export them to a USB drive, I don't need these fx and I'd like to remove them permanently...

Does anyone have a clue?

Cheers,
Marc