Actually, there's an error in the display routine, between full precision decimal and scientific.
This is asin(0.5) with the different display modes
(* 5.2359877559829888 (^ 10 (@NEG 1)))
0.52359877559829893
Depending on which display mode is called out, the displayed precision is different, and, in the case of fixed point, erroneously displayed
the "correct" value from M11 symbolic engine:
.52359877559829887308
TTFN,
Eden