Hey James,
this is likely due to the fact that you are starting the trace later during the process instead of at startup.
Memory tracing needs to start during startup to correctly resolve callstacks and collect all allocations.
While trace has a built-in cache, if you start the trace later it is likely that the initial information about modules or callstacks is no longer cached and you end up with missing information in the trace file.
Could you try running the same trace with an additional -tracefile or -tracehost as Editor parameters?
This should start the trace during startup and correctly resolve the callstacks.
Kind Regards,
Sebastian