Hi, I have a Briefcase giving me exactly this, if I change everything except the briefcase it still shows (CD-ROM2, PCE, CDCard), and if I change the briefcase it goes away so it's definitely the briefcase, all around it's bulletproof built but it has a weakness, the briefcase is mostly circuits for audio mixing, extra memory (ram), and memory for storage (saves), there are extra ram in your arcade card and it could be the one gone bad but less likely (easy test by trying another System Card), so I would guess it's the ram in the IFU that starts to deteriorate,
It would only need one or a few internal transistors failing to create it, and these circuits are getting old, other more mass produced
circuits are less likely to fail, most of the standard ones are still in production today while these ram circuits are long gone in production.
IC102 M5M5256BFP-70 (Mitsubishi) SO28 SMD / 262144-Bit 32768-Word by 8Bit S-RAM
IC103 M5M5256BFP-70 (Mitsubishi) SO28 SMD / 262144-Bit 32768-Word by 8Bit S-RAM
Located on the RAM Board.
I can only see it as giving me weird distorted pixels in the cinema sequence of Rondo X, so it's not that annoying, none in gameplay.
The circuits are probably storing the data parts of the cinema sequence in a certain part of the ram not usually used in game and therefore
not seen otherwise, if a game would use those bits the information would probably get distorted too.
One day I will see if I can't get any NOS circuits and install and see if that fixes it and then we'll know for sure.