I'm not saying it's not the batteries but a 980L's bezel, reflector and pill have to be seated just right for everything to work. The pill will thread right out of the head in either direction and on some lights, you can't simply snug it against the reflector and call it good.
I devoted some attention to this in my review. https://budgetlightforum.com/t/-/2284 It is very, length sensitive on the inside, I suppose you could say. If the pill is seated too deep or too shallow, it will change modes at will or not work at all. You might try screwing the pill in or out a little.
Foy