So I found a weird bug in Max 8 where [deferlow], when patched before a [delay] or [pipe] which is triggering something from the pattr system (e.g. a preset) causes Max to crash immediately when the scheduler is set to overdrive. I have been able to reproduce it on several machines (all Macs running the latest Mojave). Turning off overdrive solves the problem. Different signal and i/o vector sizes don't seem to make a difference. Doesn't matter if DSP is on or off either.
I am using lots of mc objects and lots of objects added to pattr so that probably has an effect as well.
The workaround is simply to put [deferlow] after the [delay/pipe] (i.e. right before it calls the pattr system)