Fan buzzing

My fan has started buzzing at medium to high speed (recording:

I took it out and made sure it was clean and nothing was caught in it, so I am concerned that it may be off-balance. I can tolerate some air whooshing sounds but the buzzing is quite annoying. Anyone know if this is a known issue or there’s a way to fix it?

Hi, could you fill out a support request around this?

Was this resolved? I think I’m hearing the same issue. The buzz is pretty loud, hard to ignore. It comes and goes.

i was sent a free replacement fan, which has the same issue. i currently have a support ticket open about that.