Does the userportal.adaktu.net domain name mean anything to you? You are getting certs for that name regularly too. Is it a clue?
I looked more carefully at your cert history for adaktu.net and www and see something unusual. Usually, ACME clients renew 60 days after issuance. They don't have to it is just common. But, yours has been renewing every 56 days with some stray variances. In fact, it even briefly expired Dec25 2022 for 2 days.
This probably won't help you but I'm hoping it might remind another volunteer of something. And, it might point to this not being an auto-renew ACME client but something done manually as @jsha suggested earlier.
