Hi @SidPrice - I moved this post to a new topic.
I took a quick look and I was not able to duplicate this behavior. However, I think that I know what you are seeing. That current ramp looks too smooth to be real data, and I suspect that your computer lost some samples. This can happen if your computer gets overly busy or you are using significant USB bandwidth for another peripheral. You can see dropped samples statistics in the log files. On windows, you can find the logs under:
The log name is the starting timestamp in UTC time.
You can also open View → Developer. You care about skip_count which is the number of times a sample block was lost. sample_missing_count is the total number of samples dropped. contiguous_count is the total number of contiguous samples received in the current block.
Now, going back to the original question, the markers should really display something like “no data found” in this case. It looks like they are pulling the nearest valid sample’s data. A follow-on issue is what the waveform should display. A straight line is probably not the right answer…