Hi June08. I'm sorry that someone so close to you has become such a trigger. I definitely understand such a situation.

Lots of places, things, situations have been major episode triggers for me in the past. As for people, one was actually my last psychiatrist in the US, of all people. I had a rather significant transferance love for him and the anticipation of seeing him, alone, would cause mood elevation. Actually seeing him worsened it. Then he would see me hypomanic or manic and schedule the next appointment sooner than might have been otherwise. Repeat. Perhaps a little different than your situation, but still a "people" trigger. My moods started to stabilize better than ever after the pandemic struck and after moving to Europe. Away from face-to-faces with him.

Other than just not visiting your mom, which I assume you don't want, perhaps some CBT coping tools could be helpful. They have been, for me, in dealing with situation/place triggers. A particularly good one is pre-planning scenarios in your head of how you may react (process trigger) in healthy and balanced way. Really, I think understanding what your mom does/says that triggers you is crucial in this step.