These are just information message which do not force you to take any actions.
We did not hear about that issue before. If you clear all notification messages they will come back only in case you will manually refresh GUI web-page.
Please let me know if anybody else is facing with same issue.
Could you create a backup of the configuration (from the Tools->Backup/Restore page, Backup Configuration in text format) of the radio and send it to me via private message? I try duplicating your issue unsuccessfully. Maybe there is something specific in your radio configuration that could be causing this.
Still doing it on 2.5.1. I seem to notice it only when ACS is enabled. It happens when in any page except Config->Radio. For soem reason that page is different and prevents the alert from showing up, over and over.