Hey, folks!
A heads-up: it seems Twitter added some new mechanism to detect "unwanted" URLs. It seems they detect some mastodon instance URLs as one of those URLs. This will stop the crossposting to post over to twitter any toot bigger than Twitter's limit.
If you are not seeing your toots being posted even if everything is enabled, check if you're not in this situation.
https://help.twitter.com/en/safety-and-security/phishing-spam-and-malware-links