I've also found some weird discrepancies in other Southern States where the black population is scattered across precincts like a checker-board where the Biden vote share is much lower the black population.
I think in these sorts of situations, the census numbers can be a bit off on the true black population of a precinct. Also in some cases these can be explained by a precinct having a large prison population. Also 2020 with mail in voting and having to guess the precinct allocaiton of mail-in votes screwed some things up.
Is it also possible that there's a large Black Immigrant Population (I know most Haitians who immigrate to the US move to FL these days, for instance, and it stands to reason that many other Caribbean immigrants would move to FL too, due to geographic proximity if nothing else) who can't vote or don't vote?