Workflow Timer Triggered Too Early

Hi guys,
I have a workflow code that implements a selector with timer and signal as shown below:

We tried to initiate a transaction. A NewTimer was initiated with duration 60000 as shown below.
The timestamp was 2023-06-08T17:11:48+07:00. The timer was expected to be triggered at 17:12:48, but instead it was triggered at 2023-06-08T17:11:50+07:00, only 2 seconds after it was initiated.

Is there any bug in our code or is it just an intermittent glitch? When we tried using a new transaction, the timer behaved as expected.

Would you post the TimerStarted and TimerFired events from the workflow execution history?

Well, based on the history, the duration is as expected (1 minute).

I believe the log statements are from different workflow instances.

I see. Thank you for your answer, Maxim.