Transcription timestamp resolution

[Shadow-Alex]

Sometimes I get second-level resolution in transcription, like :
[00:00.000 --> 00:15.000]
[00:15.000 --> 00:29.000]
[00:29.000 --> 00:42.000]

But sometimes I'm able to get ms resolution, like:
[00:00.000 --> 00:14.720] # something like this. I can't reproduce the output now...

What is affecting this?