Thank you Francois for your response.
Here is an example where it even seems to be more than 1 sample.
First the way the data looks in EEGlab when I save the dataset.
The latency in EEG lab identifies the event as the number of samples. So I would expect the highlighted sample to appear at the 0.000 position.
Now here is what the data looks in brainstorm after input (opening the epoch file in Matlab). The event I selected is the first PNV event. First the Time variable which makes me believe I would see the 0.000 sample at index 3001, however looking at the F variable it seems to me in this case the variable is in 2999 2 samples earlier.
Here are the set/fdt files used attached. Even as a zip file it was too big for this forum, let me know if this share link does not work for you.
https://musc.box.com/s/c4f0x613nuk40xza19s5zmo86qnpvywh
Thank you so much for your assistance!
Christian