Oppo BDP-83 playback issue

[ZipGun47]

I've had my Oppo BDP-83 for 10-11 years, and it's always been a workhorse. However, two recent releases have proven to have playback issues: the Arrow Gamera set (Region A version) and the Eureka Bela Lugosi Poe set. Both releases load and have working menu screens, and sound, but neither has any picture. Other discs work fine as usual, so far as I've seen. The firmware is the most up to date version, but that came out six years ago or so, which makes it seem like a non issue. Is this just a case of the player falling prey to discs it can't play due to coding reasons or what have you, or is there some tech issue that would be causing this?