Exclusions don't matter. It is the disk sector modification that can cause problems. Some AV have problems with it. I don't think it is Avast.
Some AV do not like to be installed into snapshot. Avast can be installed into snapshot. Others can be, but scans will cause BSOD.
It is hard to say what happened on your system.
2 of the probs I had was with Comodo Cloud AV & Driver Talent.
I had excluded/added to trusted, etc files/folder/processes of Rollback in CCAV. I tested CCAV usability by installing few programs. I restarted the system. After restart I got error from Rollback & there was no CCAV & system looked little messy. So I tried to restore to previous snapshot & got Windows screen over & over something like Windows detected probs, try restarting again. I tried another snapshot & got insert Win 10 disc screen.
Only "Base Snapshot" worked But CCAV drivers were still there on the system. I removed CCAV drivers.
Now whenever I install any CCAV version, after completion install mention realtime protection disabled, apply fix. After applying fix & system restart, no probs.
It seems the mentioned prob left some remains of CCAV on the system or dont know?
I tried Driver Talent to repair card reader driver & restarted the system. After system restart got Rollback error. Driver Talent was not there on the system & system was little messy. Tried couple Rollback snapshots but system still was little messy like system looked like some of my custom settings were back to default, start menu had half of the things missing, etc...
Only "Base Snapshot" worked But Windows mentioned to scan disk for errors. Uninstalled Rollback & run chkdsk, no errors were found. Tried sfc /scannow, everything was fine.