The logical replication dump of the table I thought was 'stuck' eventually completed after 6+ hours. I guess the replication slot showing active as false is to be expected. I never noticed it before.
So there never was an issue - apart from my ignorance. Sorry for the noise.
Sorry, I should have added the publisher is on 13.1 and the subscriber 14.2. Both are AWS RDS instances. I checked the log files for the publisher and subscriber and couldn't see any logical replication errors. The publisher is a busy DB though so if there are any errors there, I may have missed them.