I'm using power automate flow to query the Dynatrace REST API, which returns JSON formatted output.
startTime is returned in EPOCH UNIX time format and I'm using this expression to convert it into a human readable format:
addToTime('1970-01-01T00:00:00Z', outputs('Compose'), 'Second')
The above expression converts 1638860388929 to 1912-06-02T12:57:37.0000000Z, whereas it should actually be Tuesday, 7 December 2021 06:59:48.929.
Why is my expression giving the incorrect output?