Hi Gautier Gillonโ, this definitely sounds like a bug/defect. So you can progress it on here with the assistance of the support team or in the support space. Or log a case with ServiceMax Support.
I do suggest you share the Time Zone values of the Technician's user record and the User creating the event and the User trying to update the event. Also step by step instructions of how to reproduce including the time and date you are scheduling for and the time and date you are scheduling for and the previous info about users.
Supportโ, any ideas on this?
Regards, Richard
~If my post was useful, please give me a thumbs up! Mark correct answers as 'solutions' so we can all find answers faster!~