I had Astra on 2 websites and both deindexed on different times. I have changed themes, one of them recovered and indexed back, but the other one is not. Bot white hat. And the recovered one is not receiving traffic as much as before.
I lost another website with not much known theme as well.
I think Bing has issues with some themes but that's not the only problem. Their spam link alghoritm is very bad and I think it also has allergy to 301 redirects. These are my observations so far.
Honestly, I don't care Bing much but ofc it effects your overall income if your all sites get deindexed.