Trace channels have swapped

I’m doing some logic in a blueprint using capsule sweeps and ray traces. One odd bit of functionality I was having was that my trace by channels were colliding against objects that weren’t on that channel. After a bit of experimentation I’ve worked out that for some reason when my object blocks custom trace channel C, traces from channel B and not traces from channel C will hit it, and when I set the object to channel B, traces from channel C and not from channel B will hit it. When I set the object to use custom channel A, traces from Channel A work correctly as expected.

It would seem at some point that the trace channels have gotten confused or something? Is this a known issue? Might there be something I need to do in the defaultEngine.ini or something to adjust this, I can work around it, but I’d much rather have a fix.