it seems that the beta 2 for now fixes both video glitches and the popping sound when you jumping through a video on youtube...the only issue remains when you quit youtube or itunes sometimes still making the same popping sound
But again, after months, the 2018 seems almost perfect with no issues....Apple can't make a new product with almost bug free, and the users/consumers are in present the QA department for Apple...nice, no $$ for QA, cost cut