I'm having a strange issue with the BH mergers file, which is that although I'm seem to be able to construct merger trees and take other useful information on the BHs from these files fine, when I'm try to pull the same information from the main TNG300-3 data (PartType5), the information is different (e.g. for the same ParticleID, the BH_Mass and BH_Density are different between the datasets).
I'm unsure what could be causing this, or if there's a step in the process we're missing?
Are these small, or large, differences? Could they be due to small timings differences (e.g. a few Myr to a few tens of Myr) between when the snapshots are written and when information may be written to these supplementary files?