I had the same issue just over the weekend. Not from vinegar dosing directly, but I vinegar bath my skimmer. I did not give it a good rinse. Essentially took whatever residual was in the pump straight into the tank. So I guess you can say I dosed it.. prob a good amount. It dropped my 8.3-8.4 down to 7.9. That was almost a week ago and my pH hasn't really budged much into the 8.0 range. I guess time and patience here since I don't see a quick fix either without raising the alk as stated in this thread.