This video shows an overview of my results.
Gold and Silver were incredibly consistent. It would always result in the screen briefly switching back to the battle screen with a Level 0 ????? on the player's side, before returning to the overworld as normal. Japanese Gold/Silver always stuck on the bag screen for a while before this happens. There was one occasion when testing on the retail ROM of German Silver where the game reset into a Glitch Dimension after finishing talking to the DUDE, but as I could not reproduce this I have to write it off as a fluke.
Crystal was much more variable. The German version is by far the most stable, giving the player a massive amount of money before returning to the overworld, as has been previously documented.
The French and Spanish versions are similar to each other, with similar graphic corruptions. Sometimes they lock up on the bag menu, sometimes they lock up on a white screen, and sometimes they reset into the "Only for Gameboy Color" screen.
The English version displays the game graphic corruption, and either resets into the "Only for Gameboy Color" screen, or it displays heavy graphic corruption before resetting/freezing.
Italian Crystal is the most varied. Sometimes it hangs on the corrupted bag screen, sometimes it sits on the corrupted bag screen for quite a while before freezing, sometimes it freezes on a white screen, sometimes it resets with the "Only for Gameboy Color" screen, sometimes it throws an invalid Opcode, and sometimes it stays on the bag screen for an extremely long time before returning to a heavily corrupted battle screen and freezing. I was lucky enough to have the last one happen while recording. Freezing on the bag screen is by far the most common result out of those options.
I feel like results are quite consistent between resets, but when the ROM is loaded up from my files it gives different results. This could just be confirmation bias though.
I will be updating the page on this glitch with the new information I have gathered from these tests!