This is weird but it’s looking like excess Nitrogen, and when there’s excess nitrogen you’re gonna lock out calcium among others..
So this looks like calcium deficiency as a result of Nitrogen excess..
Depending exactly what that medium is, depends on what route to take but if it’s soil - I’d do a week of just watering without nutes.. then start feeding again but probably less than you were before.. add a small amount of calmag to the feeds also.