I hope it is clear - it is not Manjaro servers - and it is not a Manjaro issue.
The service and the servers is provided by third party - and doing so is completely voluntary - and Manjaro has no influence on the day-to-day operation.
There is no way Manjaro can know if it the lack of service is intermittent or it is a complete take-down.
Unless the mirror provider has used the corresponding mailing list - in which case @philm would have removed the mirror from the list - Manjaro is as much in the dark as the user.
The pacman-mirrors application - explicitly excludes mirrors ( unless there is bug I don’t know off ) which is not up-to-date. If the mirror is not up-to-date - like I said - this could be intermittent - but pacman-mirrors cannot know.
The pacman-mirrors documentation clearly states - in the case of a custom mirror pool - the pool is never touched unless the user instructs pacman-mirrors to do so.
To avoid any disgruntled comments - the topic has been closed.