Can't allocate random nodes to my weapon set in PoE2

So this started happening recently. There are random nodes like Elemental Equilibrium or the jewel socket next to it that I cannot allocate to my II-weapon set.

I do have free points and obviously have made the path there, but they just say "Requirements not met". (Hell, even some small attribute nodes say that, but they let me pick them regardless) What requirements? Seems to also happen to random bigger nodes elsewhere in the tree too.

My build is kind-of borked now and apparently I can't fix it by respeccing / remaking the paths etc. people recommended.

Any tips?