wow you have good memory, i would have never guessed that a specific magenta pearl only spawns in spear master.

There is a similar issue with a pearl in garbage wastes that only spawns there in Spearmaster's and Arti's time but is on the tracker for every other slugcat also.
Also I'm getting an extra pearl in Drainage System, I went to where it shows the symbol on the map and it appears to be in the ceiling and I couldn't pick anything up there. When searching this pearl location on the wiki it seems like there shouldn't be a second coloured pearl in drainage at all, so I find that a bit confusing.