Video drift - Nuendo 11

Hi

Anyone else experiencing video + audio drift?

I’m busy doing a manual reconform using 2 guide tracks (old cut & new cut) + all the audio in the session.

As I align the old guide to the new guide, I’m noticing that every few minutes (around 7 - 10 mins)
the audio starts drifting.

I can confirm both guide tracks are same bit rate, sample rate, and the videos are both 25frames/sec.

Any idea what’s causing this? Is my final product going to drift out of sync after I’m done with the reconform???