Thank you for your reply.
This is on Gortnen
Coordinates -1008, 121, -16
Also at :-
-1022, 121, -15
-831, 70, -16
-831, 70, -31
-831, 70, -46
-831, 70, -62
-831, 70, -78
Toggling Per-Pixel Lighting doesn’t change this effect at all.
In addition, I see what I believe is the same effect at -817, 69, -49 and various places on the large pyramid, although these blocks are lit (they’re lamps). The are lit in different ways to the rest of the blocks. These are also on Gortnen.
As you can see, there are three blocks near the foreground and some further back which have a different shadow to them.