My May 2012 VSX-51 started displaying the UE22 error 2 days ago (audio still okay, though I did notice several brief audio and video "stutter" while streaming a Netflix show the night before -- but not sure that is related).
I followed step 1 in Post 1 (Contact Onkyo Support) and received a reply 15 minutes later, stating that my model was elligible for a discounted replacement. (SO YES EVIDENTLY THE REPLACEMENT PROGRAM IS STILL ACTIVE)
Your unit is one of those that can be potentially affected by the UE 22 issue. Please respond to this email and include the following information and items:
Complete Shipping Address-
A picture of the front and back of the unit, the front should clearly show the model# and the back MUST clearly show the serial#.
We can offer you a trade in option; these are the models I would suggest for you:
VSX-LX104  -  $299.40
VSX-LX304  -  $479.40
Once you have chosen a model we will send you a form to complete, sign and mail back to us. Please note that these prices include standard shipping but depending on your state, you may be charged sales tax
I responded right away, choosing the LX104 (which I considered a nice upgrade to the VSX-51).
I received the form, printed, signed, attached serial# tag, and mailed it in (scanned and emailed was not accepted).
I await the call for my cc# next week, and following that, my replacement unit. Stay tuned!
In my case, I consider $300 for a substantial upgrade to a 2019 unit retailing for $500 for my 2012/$400 unit that worked fine for 7 1/2 years a good deal and a reasonable resolution by Onkyo/Pioneer.
Many thanks to thread moderator for clear and updated resolution instructions and to all posters for sharing your experience.