isoformat() omits the microsecond from the format when the microsecond is 0.
Therefore, use strftime('%Y-%m-%dT%H:%M:%S.%f') instead.
Related Change-Id: Id6e8645362fe70b1427d45d5b44048fe47aba0f7
Closes-Bug: #1478418
Change-Id: I27059fa3476ceb51033534cc60d40047d88390d7