Originally account deletion would always delete your posts, comments and everything. This was changed in 0.19 to make the content deletion optional (otherwise a lot of posts and comments would disappear unnecessarily). Unfortunately we forgot to add the new option to the user interface for 0.19, but it was added probably around 0.19.4.
Its hard to say why the federation didnt work properly, maybe there was a network error, or a bug in older Lemmy versions that got fixed in the meantime. Or there is still a bug which only happens in some cases.
We also added a new maintainer, @[email protected]!