( Free42 , DM42 ) Overflow is not trapped of basic matrix arithmetic,

[Werner]

Update: in Free42, it's a Preferences menu option ;-) it's clear per default, as that is the 42S behavior
in the DM42 you can't change it.

It turns out that this is 42S behavior.
42S matrix operations act as if F24 is set all the time, e.g. :
(with F24 clear)
1
ENTER
NEWMAT
9E499
+
ENTER
+
EDIT
yields 9.999..E499, MAXREAL

Don't know which version of Free42 changed it, it isn't in the history.
At the very least, the DM42 acts as the real 42S in this regard.
I'll ask Thomas about it
Werner