They all have been busy with fixing the S2X Multistream and since we are having an good conversation
there is no need for others to but in until i give you some wrong info
I have now accully run the latest update and for me all is still working with PIP and QuadPIP.
I cant find Youtube TV but there is an Youtube plugin so i download and install that and all is also working fine
so now i am not sure why you have this issues.
But as allways when we do updates, new image flashes a file can be corrupted and we get stranded with no clue why just my Vu+ want work as good as all others.
So my only suggestion for you is that you just need to reflash and after reflash install all the plugins needed then run a full image backup and save on your Computer.
Then do online update i allways keeps an latest full image backup in case anything goes wrong when doing updates.
and i also let a lot of people do updates first and see if they report any problems before i jump on the newest update.
But with that in mind, updates are important so we should all use them but sometimes when all is working just fine there is no hurry.