If you don't understand where the lightning yield is coming from, you are the yield!

In my opinion, miners should only include sub-1sat/vb in blocks if they serve the hygiene of the UTXO set.

The truth is: there is no working price model.

I think they have migrated to lnd 0.19.2. and not increased their gossip defaults. Another big node ran into the issue some weeks ago but was able to solve by increasing the defaults

https://github.com/lightningnetwork/lnd/pull/10096/files

But only guessing.