The Master System port of Rainbow Islands was notoriously bugged and could not be completed, but was the Mega Drive version too?

According to Wikipedia the Master System port of Rainbow Islands shipped with a game breaking bug:

The European version of the Sega Master System port contains a bad glitch that crashes the game after Level 7, sending the player back to the title screen. If the level select code is used to access Level 8, the same glitch occurs at the end of that level completely preventing the player from seeing the ending. The Brazilian version has fixed this glitch

I never played that version back then, and only had access to the NES port so I can’t confirm this by personal experience.

I have vague memories of a friend of mine telling me that the Megadrive port was also bugged. Apparently the port has two modes: the default one – a "remix" with swapped enemies types between the levels and the original arcade one. They claimed that if you played the "original" version there was no way to access the three secret island since the game would not detect the seven big diamond being collected, meaning you would be always forced on the "bad" ending.

This seems to be backed by this World of Longplays video.. You can clearly see how the game recognizes that the 7 big diamonds were collected but plays the "bad" ending afterwards.

Is this real? Were both Sega home console version of the game bugged and impossible to complete with the best ending? Or is this actually due to some emulation bug that only happens when someone tries to play the game on an emulator (meaning that probably some virtual console versions and/or ports of the Megadrive version of the game COULD be affected)?