I have a PowerApps front-end which creates entries in a SP list. Once a record is added a Flow take details including start and end date/time and creates an Outlook Calendar entry using Create Event (V4). Although I believe I have the date/times in UTC format in SP I get an error in flow that prevents me from saving. The error is:
Flow save failed with code 'OpenApiOperationParameterValidationFailed' and message 'Input parameter 'item' validation failed in workflow operation 'Create_event_(V4)': The parameter with value '"@outputs('Get_item')?['body/VisitStart']"' in path 'item/start' with type/format 'String/date-time' is not convertible to type/format 'String/date-no-tz'.'.
So I have tried using the Flow function Covert Time Zone but it now adds 1 hour on so that the calendar entry is wrong. Here is the convert formula:

I'm going round in circles!!