Ok. So, what I just replicated a few times is this issue:
I applied the Audio effect "Telephone", followed by "Shortwave Radio" and after that applied the "Cathedral" effect. So far so good. Then when I want to listen to the audio, HitFilm crashes. Just tried this 4 times and each time this bug was replicable.
I wonder if it's because one of the effects is derived from another or something, as this is a common issue I frequently encounter with other effects, but I forgot to report those.