Yep, I'm seeing this more often. And, I do not respect this from any Book. I won't mention names, but maybe you need to see if your Book is attempting to give you a lesser line so to keep you away from certain points-spreads or totals?
Point-spreads, where you would likely play, and they see it as their benefit that you don't see this line change.

Example: If you've already played Boston College strongly at-3 1/2, it's likely this certain favorite Book, when those syndicated line changes popup, say at BC-2 1/2, you'll likely only see the line at -3, or maybe 3-20?

Another cheap shot in my opinion. It's not like they need an additional winning edge.