(Usual disclaimer: please note that I'm just another Forum user here, I'm NOT an Ubuntu Developer and/or Ubuntu MATE Developer).
Is your Ubuntu MATE 22.10 Beta installation using the Polish / Poland locale by any chance? If that's the case, you may be experiencing the same bug for the "ayatana-indicator-datetime" package that I found was reported for Ubuntu MATE 20.10 ("Groovy Gorilla") and that is noted in the Bug comments that is also affecting Ubuntu MATE 22.04 LTS ("Jammy Jellyfish") - "Wrong time display in Ubuntu Mate 20.10 when LC_TIME=pl_PL.UTF-8":
I've found the same bug / issue reported in the GitHub "upstream" git repository for "ayatana-indicator-datetime":
The same bug was discussed here in the "Ubuntu MATE Community" discussion forums in the following topic started about a week ago (on 24 September 2022) by "Marcin K" (@marcinkk) :