Looking like heat stress/nute burn/toxic salts buildup.
Are these just a few weeks or less from finishing?
Hard to tell much more with so little info like growth stage, nutes, lighting etc. Hard to mistake that HPS glow but still best to know how big and distance from canopy.
Growing FF soil there about 4 to 5 weeks into flower had ph problems prior so iv run dolomite lime and calmag water thru them for about 2 weeks now. Temps around 80-85 just gave it a nute feed 3 days ago but prior to that it's just been water for the past 3 to 4 weeks. I flushed them around 3 weeks ago down to 800 ppm run off. And the run off ph was 6.2