I'm sorry you're dealing with this. I've had this issue with my T, where he can be very supportive, then suddenly decide he's going to push me on something, sometimes seemingly randomly. He says it's part of his role to push me rather than just support me, but it can be bad timing.

For example, in August, my husband and daughter got Covid shortly before we were going on an annual beach trip with my family that my D was very excited about. I was worried that with the timing and my parents being elderly (so higher-risk), we might not be able to go. Instead of being empathetic, my T kept saying how it's actually the perfect timing for us to get it and even went so far to say that I was taking on a "victim mentality," which isn't a good thing. (And this was after he'd stayed virtual for nearly all of 2 years for fear of getting Covid.) And I wasn't all like, "woe is me! How could life be so unfair!" More "Oh no, I'm worried the vacation might not work out." It caused a bit of a rupture.

Anyway, so yes, I've experienced this. It's difficult. Have you tried talking to her about it? Like what you said here, that she can seem wildly different from week to week?

Note: We ended up still being able to go on vacation (though my H masked the whole time around my parents because he was still testing positive (it had been more than 5 days, and I was masking around him to avoid getting it). But when it was first happening, we had no idea if it would work out (or if potentially one of us could have gotten pretty sick). And my concern wasn't about me, but my daughter getting to go to the beach with her grandparents, who she adores.