I don't know if the complaints presently relate specificallly to the old HDMI issue, but i am wary of the B stock units even though they should be certified as working and come with the same warranty.
Are you really just inheriting someone else's problem?
Company takes back faulty unit. Attempts a fix of the most obvious fault. How much QAQC happens before it goes back out to sale as B stock? Was the problem they fixed not all of the problem? Caused by something else that wasn't replaced in the unit?

Here is a recent review from Amazon on this specific Onk.

.0 out of 5 stars Sounded AMAZING but Broken in Less than 2 Months
September 29, 2019
Style Name: TX-RZ830Verified Purchase
When we first received the Onkyo RZ830, it was working perfectly. Setup was a breeze and the sound was a HUGE upgrade from our aging Harman Kardon. However, little things began to act up - the on screen menu began to lag a lot, not by a second or two, but you had to wait more than 30 seconds for any button press to register. Then the wifi connection became more and more spotty, until it never worked again.

Will be contacting Gibby's for issue resolution.

Last edited by chesseroo; 01/17/20 10:50 PM.

"Those who preach the myths of audio are ignorant of truth."