I don't see any other complaints on this, so perhaps it's unique to my system.
In the last few weeks, I'm noting that seveal sites, while loading quickly, will lock up for several minutes, and often need Task Manager to shut down. I thought it was my ad blocker, but it wasn't. Affected sites include Amazon, ebay, palottery.
Started disabling extensions, and found the problem to be Malwarebytes Browserguard. I can work without it till fixed.
Hoping this info to be useful for anyone else who may come cross it.