Interesting.
I experienced a similar failing with one of these models some years ago.
On that occasion, I got to the very bottom of it, all 'i's dotted and 't's crossed, by using protocol analyser tools to inspect the recordings. The problem was interesting; the DVB broadcasting standard basically defines various bit settings for various functions, and in some cases unused bit combinations are specified as being 'reserved for future use'. One of the UK broadcasters had begun, apparently in error, using hardware that set these bits which caused these Sony boxes to malfunction. Basically, the aspect ratio tended to be wrong, with some 'widescreen' broadcasts shown in 4:3 format with pillarbox bars.
In my view Sony were entirely at fault as the DVB spec, like any decent protocol spec had forwards compatibility build in and basically said that, at the receiving end, any reserved bits should be ignored, ie treated as if they were zero. Freeview boxes that did so continued to function, whereas Sony's buggy boxes didn't. Sony's firmware clearly wasn't observing the 'ignore reserved bits' rule. They also refused to release a fix, and instead resolutely blamed the broadcaster, who had to stop setting the 'reserved' bits, it all took months to resolve.
With all that in mind, I'm not at all surprised to hear new problems have crawled out the woodwork, even if its a completely different problem,.