Weird marker

Quick question (maybe), but I’m currently editing some audio and noticed this weird yellow line across a few tracks. I’m just wondering what it is and if it’s possible to clear it. It’s snapping to the grid, preventing the audio from snapping at the start of the region like you’d expect. Is this an xrun? Because those used to show up in the Location Markers bar instead.

This is what it looks like:

You've pressed the key binding ("v") that sets the region sync point. These are very partially described here:

To remove them, select all affected regions, right click on a region and select "Remove Sync Point".

Thanks, I must have accidentally pressed V while trying to press another keyboard shortcut.