I'm running into an issue where I can only do 7 levels of queue tree. ie, parent and 6 levels of child queue. the next level is all 'red' invalid.

I can't find any documentation about this limit.

Anyone know if this is a fixed limit or of there's some way around it or what?

This is a Linux kernel limitation.
TC_HTB_MAXDEPTH is arbitrarily set to 8 by default in Linux. See https://github.com/torvalds/linux/blob/ ... kt_sched.h
Linux can be compiled with that file changed to achieve deeper queue depth.