markers being added 30min left of mouse click

When right-clicking to add a marker, the marker gets added about 30 minutes earlier than the point where I clicked. This is in the OSX native version of 2.7, rev. 4225. It’s a little inconsistent, but I think it happens after I scroll right to view more audio. Has anyone else encountered this? I didn’t find a bug/forum post, but I’ve been blind before.

I do have the same problem, running ardour 2.7 rev 4483, compiled with VST support. Maybe it’s time for a bug repport…