sounds like a potential issue with the youtube cdn node you're being sent to when browsing youtube.
it's not an uncommon problem around here - a mix of issues with either netflix, youtube or the google play store. it's usually resolved by getting a new IP address from VM - and forcing that to happen is certainly worth testing to see if it has an effect on your problem. you can do this by putting your hub into modem mode and connecting a single device (laptop?) to the hub via ethernet.
if you have a 3rd party router and are already using your hub in modem mode then you can try a different method.. let us know if that's the case, along with the make/model of the router and we can go from there.