Status check alternates MX record being okay one day then incorrect the next

I’m finding that I receive a status check change notification reporting that the DNS MX record for a domain is incorrect, then the next day I receive a notification saying that it’s correct. This repeats every day or every other day.

There haven’t been changes to the DNS for the domain since the start of January (so about two months ago) but I’m receiving these emails all the time. I use freedns.afraid.org as the DNS provider and have glue records set up for the domain the box is hosted on.

Additionally, when it’s reported as “incorrect”, it states that the MX record is set to it’s previous value before I moved it to my MiaB installation.

Any ideas?