It's probably about once a day on average, but sometimes a couple times per day and sometimes several days at a time with no issues. I downgraded most of them that were having problems to 2.4.3, which does seem to have resolved both issues, but I do that the management interface isn't responding on right now, and has currently been that way for about 2 hours (but the clients are still working fine). I'll be happy to collect some logs for you if that will help.