I am pretty new to LrTimelapse so please forgive me. I just imported a sequence created with my GoPro. One thing I am noticing is that almost all images have an interval of 9 but at position 45,245,319,324 I get different intervals like 16, 36 and other values. When I delete one of these images, then the next one will flip from 9 to the higher value.

Does anybody know why this happens?

Seems as if the camera has not been triggered for some reason. May be it went to sleep and it took quite long to wake up.
But finally it got nothing to do with LrT.