Logic Pro busses are silent when bouncing projects

Busses muted when bouncing?

Since logic updated recently, for some reason, my busses are not making any sound when I try to bounce the project. As an example, I always have a separate bus called Harm Out (in photo attached) with my guitars, bass and other harmonic content sent into it, so that I can cut the mid channel midfrequencies to carve out space for the vocals. This bus is then output to the stereo out, and when mixing, I'm getting a full picture of all the channels coming through the bus and into my monitors. But as soon as I try to bounce it down, or "share" (airdrop to my phone to listen on the go), I get nothing but my drums being heard. My drums are routed to a summing stack, which has no such issues, but for some reason only my separate busses seem to have these issues (reverb busses etc.)

The only way I can get an audible signal out of the bus when I'm trying to bounce, is to set the channel to record, and let the song run through, to record onto the channel whatever signal it is recieving. Then suddenly it's perfectly fine when bouncing. In the image attatched, that is what you can see (the blue channel is the Harm Out bus after having recorded it's input.

I haven't changed any of my base settings, but have tried turning input monitoring off, or monitoring for separate channels etc (in settings).

Does anyone know why this is happening suddenly, and how to fix it?

Thanks in advance xxx