Logic Pro mastering assistant causes distortion in offline bounced file

I'm trying Mastering Assistant. I'm bouncing many files from the same document. Some have a distored sound in the bounce file, some don't. When I turn off the Mastering Assistant, the bounce files do not have distortion. When I bounce realtime the files do not have distortion. I'd like to eliminate the cause so I can continue to use Mastering Assistant.

Today I started with a blank template, added midi files to tracks and recorded an instrument to a track. I bounced five short sections of the file one at a time, then muted a track and bounced the five sections again. Some of the bounced files are distorted, some are not. Nothing sounds distorted on playback within Logic Pro.

When I turn off the Mastering Assistant, the problem with the bounced files goes away. When I switch from offline to realtime bouncing the problem goes away. Thus, there is an interaction between Mastering Assistant and offline bouncing.

Realtime takes much longer but Mastering Assistant sounds better than my previous mastering settings. Any idea what I can do to keep Mastering Assistant and offline bouncing?

My computer is iMac Retina 5K, 27-inch, 2019 (Intel processor)