This is my 'Otaara Hwa Yuan Bay'. First pic shows worst leaf. Was like that when I got it lil over a year ago but has gotten worse and now other leaves are showing signs. Grow under 400W MH at aboout 2'/1400fc. Bloom just dropped last month after about 7 weeks.
I don't see any unusual signs. The first looks like physical damage that just got worse (it happens) and it shouldn't go quickly. Might get worse and might not. The second photo shows tip damage often associated with not flushing the pot often enough. Salts build up either from tap water salts (like calcium, iron, etc.) or fertilizer salts. Either way, you might want to flush it better (run water through pot more.)