Neo Geo CD emulation has been impacted by a speed bug, which means that games now run too slowly. A setting to boost the game speed up results in missing visuals (as shown in the tweet reply below).
Polymega manufacturer Playmaji says it is aware of the problem, which it claims didn't reveal itself during the testing period. It will be fixed in the next system update.
However, this isn't the only problem that has been detected by Polymega owners. Some fan translation patches are reportedly no longer working post-update, while other users are saying that audio is missing from certain games.
Polymega system update v1.1.30 launched at the end of 2023 and introduced refresh rate control, adjustable game speed and the ability to rotate the display, as well as support for the new EM05 Ultra module, which allows N64 titles to be played on the system.