Well, so much for the Minolta theory!
The inside of my A7 is exactly like your A7ii.
I can't see how it could be the LA-EA3 at fault, there's surely nothing inside it that could cause these reflections. As you know I have the LA-EA4 and as an adapter, it is considerably more complex than the LA3 but there is nothing in there that could cause reflections, only a mirror that could be very easily damaged from front or rear.
Sony A7, A850, A77, A700 || Sony>> 70-300G, 28-75 f2.8 SAM, 16-80CZ, 50 f1.4, FE 28-70 OSS, FE 24-70CZ f4 OSS, LA-EA4 || Minolta>> 300 f4 G HS, 200 f2.8 G HS, 100 f2.8 (D) Macro, 50 f1.7, 28 f2.8, 28-135 f4-4.5, 70-210 f4, 500 f8 Reflex, TC x 1.4 HS, TC x 2 HS. || Sigma 21-35 f3.5-4.2. || Tamron SP 24-135.