Strange outlook calendar movement

The public calendar recently started moving events either a day foward or a day backward. If I put an event on monday with 9am-5pm, “SOMETIMES” the calendar either moves it forward to tuesday, or back to Sunday, or add a day all the same. I thought that it was a date/time issue on the users computer untill it happened to me. then thought date/time was wrong on server. thats fine too. Just started about a 2 weeks ago. Wonder if anyone seen this before. thanks!