Antoine Riard a LN dev found critical vulnerability that allows for attackers to steal users funds from LN channels called Recyling and Pinning Attacks.
He then left lightning labs to focus on bitcoin core.
The solutions proposed in the lightning devs mailing list of this fix are soft forks to the mainchain. Suchas OP_EXPIRE AND OP_CHECKCONtRACTVERIFY.
😅