Sanderxpander - only one of the tracks has more than one take, all other take lanes show only one take. Good thought....
mettelus - tried the bundle save and that actually did get rid of the artifact (great idea!) --
BUT, interesting thing, I was deleting several older tracks in the project to keep the size down, and found that two of the tracks (the ones that didn't have lines on them, interstingly), once deleted, took the lines away with them as well. If I undid the delete, the lines would come back again. On just one of them, freezing the track made them go away also. Once I deleted down to just one of the two suspected tracks and one other track (to reference the presence of the lines), it did look like those lines were following transients on the uncorrupted bass track. SO, looks like it's a bug.... trying to decide if it's worth talking to tech about or not - I don't know that anyone else has come across this (that I could find in the forums) so don't want to waste their time on a personal issue, lol.
Thanks all for the help - and Leadfoot - you were on the right "track" so to speak, too!
todd