Custom bezels in mame do not show up

Hi everybody!
I have EmuElec 4.2 running on an Odoid N2+ and I ran into following issue:
I downloaded and installed the bezels from the Updates&Downloads section from The Bezel Project but I cannot manage to get them displayed for the Mame and FBNeo emulator. For all other installed systems I use, the bezels are shown correctly.
The game setting to enable RA bezels is turned on and also the png and cfg bezel-files in the corresponding folders are here.
Mame and FBNeo only show the default EmuElec-1080 bezel.
Even manually copied bezels for Amiga work.
Any idea what the cause might be?

Thanks for your help,

This is a bug that has been fixed for next release, meanwhile, change the folder name to arcade

Perfect. Thanks a lot!