There is currently a fee bug on Monero, that the wallet doesn’t automatically bump the fee when there is a backlog. This fee bug is causing sync issues with many wallets. The bug has already been solved with Anonero.io, and other wallets will be rolling out fixes shortly.
There are rumors that Nostr's creator is behind a spam attack. Simplified Privacy addresses this and has a ready working solution: https://simplifiedprivacy.com/monero-attack-nostr/
Tor Browser Onion: http://privacypkybrxebcjicfhgwsb3coatqechwnc5xow4udxwa6jemylmyd.onion/monero-attack-nostr/
He posted it earlier. Then when asked if he was behind it, he said "maybe"