Starting in March 2024, my Outlook calendar ICS export failed to include a time zone definition. This caused the times to show up wrong when I import the ICS into Google Calendar. I managed to correct this by changing the time zone definition, which can be done automatically using scripts.
I import my Outlook calendar in Google Calendar. The way this works is that Outlook generates an ICS file, which can be accessed via a URL, and which is updated each time I add or change appointments in Outlook calendar. This ICS URL can be imported automatically in Google Calendar so that my Outlook appointments appear in Google Calendar. However, recently, the Outlook appointments started appearing at the correct date but wrong time in Google Calendar. An appointment for 15 March 2024 10 AM would actually show up in Google Calendar as 15 March 2024 7 AM (!). This made it pretty unusable.