Probably too late in flower (day 57) to fix it I’d love to know if this is a simple fix for future issues, or if this comes again on another run. Is this just Ca or Mag? I’ve read some deficiency write ups, but man, I don’t trust my experience (lack there of) in diagnosing problems yet... Any help is greatly appreciated!
If you haven't given any cal mag since flower it is probably cal mag. Do you have little rust colored dots starting on the leave edges? But looks like nute burn also. What nutes have you been using and how often? That will help someone better diagnose you. And what's your ph? Soil grow?