Ok, I misspoke a bit. A couple of the changes of command were Phibron turnovers aboard LPD-18.
But it has been weird recently. In Sept 2021, CAPT Graber relieved CAPT Schrum. 15 months later, in December 2022, CAPT German relieved Schrum. In March 2024, 15 months later, CAPT Biggs relieved German. So far, normal. But then in October 2024, after only 7 months, CAPT Rule relieved Biggs, and only 2 months later, in December 2024, CAPT Dean relieved Rule. Dean seems to be the current CO, with 8 months tenure.
So it seems Biggs left early, Rule was interim (maybe from the Phibron staff?), and then Dean came in to backfill.