Every strain I've ever grown almost gets those yellow tips on the leave's even when I deliberately feed low ppms. If it gets worse, spreads up from there and/or the leaf margins begin to look all 'jagged' and their tips start yellowing then those are signs of nute burn.
I used to burn plants all the time or end up with toxic salts buildup that starts frying leaves around mid-flower and just trashes them until I found out more about VPD, Vapour Pressure Deficit. We have very low RH here, (20% at 80f right now in my veg tent), which causes the plants to transpire a lot more water than they would at a higher RH. Even at modest ppm levels it will pull up more salts than it can use so they get stored in the leaves until it builds up to toxic levels and the leaves basically fry from the inside going all yellow/brown all over the leaf surface and going crispy and thick feeling. Mostly happens first with lower and older fan leaves but can start up top if leaf temps have been a shade too warm for a long time then the plant is running more water up there to cool the leaves and the salts buildup is worse there.
I see this on lots of posts with people asking what's going on but get answers like 'more p man!', 'low k man add more!' and stuff like that. Adding any more salts of any kind is just going to make it worse. The minerals in tap water are all salts too and contribute to the problem as well.
There is no cure but you can slow the progression by flushing really well followed by a low dose of balanced nutes. Don't wait for the pots to get dry if in pots as your plants will starve until fed but it can force the plants use up some of the forced nutes if there's none in the root zone. Easier with hydro.
No problem in sight yet.