Roomba gets "stuck" in certain locations

There are three locations in my house where my 981 consistently gets "stuck" and requires a job restart. Since I'm not usually home when he runs, this has become very old.

1) A location in my kitchen where there are no obvious obstacles. There is a low pile entry rug, that's it.

2) Leaving Bathroom #1 where there is a transition threshold from tile to wood flooring, a drop of about 1/2".

3) Leaving Bathroom #2 where there is a similar transition with less of a drop.

Measures taken:

1) Brand new, OEM battery.

2) I have disassembled way down (to exposed PCBs). Blown all dust out of everywhere. Cleaned all sensors.

3) Using a tablet, checked wifi signal at all locations. 2 and 3 are strong, 1 is less so but still not bad.

4) Ran through the BITs, all sensors passed. Even when hooked up to the USB port.

5) Endless reboots.

6) Several factory resets.

Does this ring any bells for anyone? I like Phred. I need Phred because I have a golden retreiver. I just bought new stuff (filters, etc.) for Phred. I don't want a new Phred.