Might it be the Alby nwc service struggling from time to time?
Discussion
I initially thought that as well but nostr:npub15pl6u3s6dlq0hfskercdu74jd6w6ec0hzcrg434nhgj4ylvrm7fq8e8439 does not use Alby and others who have mentioned the same issue over the past year have not all been using Alby, so I'm not sure.
I do understand Kenald was talking about an Amethyst dev wallet stopping the donation from going through, but still. It's a thing.
I just reshared my comment asking others if they have the same experience. Already someone else has commented.