With the active items that contribute to the Musician transformation, I've noticed that while touching them multiple times in the same run doesn't add more counters to the transformation (as expected), getting the items directly through things like D2147483647 doesn't seem to be accounted for, which can lead to the player getting the transformation much earlier than expected. This also happens with actives with on-pickup effects like Rune Sword, which can lead to too many or even infinite runes.

This is most noticeable when using mods like Swapable Active Void, which involve constantly giving the player active items directly.

Repentogon has a callback (MC_POST_ADD_COLLECTIBLE) that seems to specifically check if the player took an item for the first time in any way (rather than just touching the pedestal), so maybe that's worth looking into? I know this mod uses a custom library, so I wonder if it's possible to use both interchangeably...