I have just found a weird one.
Using the wide angle front lens on my 18-140mm lens with the camera set to P it refuses to focus using the viewfinder but is happy to do so using "live view" and the back screen!
On "intelligent" setting and auto flash it is quite happy with the viewfinder. This is the setting I used in my workshop picture.

Sorry, I got it slightly wrong - in the first case it focusses in the viewfinder but refuses to trigger the shutter. Using "live view" it takes the shot.
Hmm, I will try putting it on auto flash on the P setting, hang on . . . Nope, only wants to work on live view. This is OK for what I wanted to do, flash might have attracted to much attention in a public space. (Seems we are not supposed to take pictures in the malls in town.)
But it is weird! Electronically the camera does not know the w/a is there; practically it focusses but gives a small red central square and a red, sort of, bracket round the central third of the f-o-v in the viewfinder when the shutter release is fully pressed.
Setting the metering to full screen the red bits, though lots of little squares now, still appear but it takes the shot. It was a high contrast, sunny window in the centre, light shadows around. Need to play more.
Reckon its a dodgy algorithm!
Oh, noticed that there might be film/coating separation starting on the front lens of that cheapo w/a lens. Little bubbles like you see with badly applied protective films on phones. It does not seem to be a protective film here. No obvious sign of it degrading the image so far.