Many reasons, but the ones I’ve seen is when TX is stuck and HTLC expires. It’s a protection against bogus TXs (I am n00b here so it may be not accurate) 🐶🐾🫡
Discussion
This really needs to improve and become more stable because I don’t think Lightning can survive if people keep having their channels forced closed, lose a bunch of precious sats settling the closure and then they need to spend even more sats to reopen another channel.