No, I don't think that is the case, I've heard the "from what I've been told" line lots of times when a ministerial stooge has been wheeled out to defend Johnson. I also think a lot of ministers have been avoiding he spotlight on Johnson for a long time. Truss, Gove and Sunak have really only ever done it when they've had no option. Even Patel rarely does it. Coffey has been wheeled out quite a bit recently. I don't see any recent change in their activity
Raab, Dories, Shapps and Rees-Mogg have always been the standard bearers with Coffey, coming into play a lot more recently. Occaisionally its Kwarteng, Javid, Barclay or Wallace but there's a whole bunch of the cabinet who almost never put themselves out for him. Sharma, Trevelyan, Zahawi, Eustace, Lewis, Jack, Hart. Even the others who attend Cabinet like Braverman and Malthouse, rarely go in to bat for him
The avoiding being tainted by Johnson has been going on since he formed the cabinet
I just don't think Sam Freedman whoever he is, is making a valid point. I mean he's right to a degree but it isn't something that's just started, it started the day he formed the cabinet