All custodial accounts will suffer from liquidity drainage. Always. Why? Because many of their users are abusing the swap features and the node managers do not have time to fix these drainage. Try again later and you will see that is working.
Also remember my warning about SN "self-custodial" way? #523570 And this is just the beginning. SN only throw the dead cat in the others garden. Most of the SN users are not going fully self custodial but using these another custodial ways... no different from any CCs.
Also keep in mind that SN is using a method similar to LNproxy + hold invoices. That is adding a lot of complexity for zaps.