Matrix editor bug in Free42?

[JSBach]

Hi,

if I create a matrix in Free42 and edit it in the Matrix editor, I get the edited matrix in X (correct) and a 0 (zero) in Y, which I think is incorrect.
(Free42 2.5.21, Windows.)

Stack before matrix editor:
T: 1
Z: 2
Y: 3
X: [ 2x2 Matrix]

After matrix editor:
T: 2
Z: 3
Y: 0
X: [ 2x2 Matrix]

IMO this should be:
T: 1
Z: 2
Y: 3
X: [ 2x2 Matrix]

Or did I overlook something?

Regards
JSBach