Hi Ludwig,
We checked your data again and found out another reason why Reach M2 may lose time marks. As I see, you are shooting at an interval of about 1 sec, and the update rate is also 1 sec. But it’s better to set the update rate higher than the speed at which you take photos. That’s why you can set 5 Hz or 10 Hz update rate or set a longer shooting interval.
Also, you can update your Reach M2 to Reach Firmware 27.1, which we’ve recently released. It includes the fix of the issue with missing time marks.
I guess if you update the receiver to the latest version and increase the update rate, this issue should be solved.