All my 4 THR-22s have the latest software version 0x01B5.
Last Friday I installed band-stop filters at the input of all of them.
On Monday, one of them experienced a blank recording just like before.
Yesterday, another one had the same issue.
Today, another one had the live buffering issue.
So, for me, the new software version hasn't fixed the issue, and the band-stop filters haven't helped at all either.
Conclusion: it seems to me that it must be a software bug.