I'll bet that happened right after they went into flower.
It's pretty common, when I transition from 16:8 to 12:12 my fan leaves do that.
It's a major shock and flowering needs are different, nutewise as well.
When I transition from LEDs to sunlight too abruptly my fans look like that, and worse.
The plant will take what it needs from the fans/storehouses, to keep the new growth happy.

What's important here is the new growth.
That looks pretty good from here. (mo'betta pics would be nice.)
Jus' leave the fans alone, the plant will drain,and then drop them when she's used them up.

Watch the new growth closely, and get back to us if that gets hinky.

In short?
No worry.

Aloha,
Weeze