Have you tried extra cal-mag?
I don't see a problem if it's only a few here and there. It's does not seem like your crop is struggling at all. Id see concerns if it was rapid all over and over a short period of time. Def keep close watch ofcoarse
Yeah, overall crop seems much happier than it did last cycle when that tent was _much_ more dry and warm. I'm going to add a bit more cal-mag to my water next time, but I won't make any more changes unless things keep getting worse.