Why did this happen? (K/P def, senescence, wind burn, other?))

[elcoloan]

two lower branches of my 6 weeks flowering plant (grown in coco with megacrop, water/fed daily) just slowly dried after she started flowering... didn't really loose their green, and other branches that are shorter and less in contact with light are healthy green and flowering little buds...

these two just stunted and started getting dark green/brown from the tips and borders, not dry but similar. here are some pics of one of the branches. i was considering K and P def, senescence or wind burn.... what do you think?

 

[Waira]

:smoking: I get this too on rarer occasion mate, on the outside photo plants,.. some grow buddies here as well,... unaccountable! No sign of trouble of any kind, they just shut down, wither and dry.... usually it's weaker scruffy branches, so no significant loss there,...

 

[elcoloan]

oh ok, thanks!