RREF with mixed mode matrix

[Wes]

I was working with a matrix today and ran into something unexpected.
(49g+, 2.09)

The matrix was
[[ 12 -2 3 4 -75.9 ]
[ 10 -3 -1 9 -24.7 ]
[ -4 10 9 13 -19.1 ]
[ 7 12 1 10 -125.8 ]]

Notice the left columns are exact while the right column has decimals.

If I use either
->NUM RREF
or
XQ RREF

it produces the correct approximate and exact answers respectively.

However, if I just use RREF (or REF) on the original matrix, it seems
to get really confused. The resulting matrix is not in Row Echelon
Form, nor does it have the same solutions as the original matrix.

Anybody else notice this?

-wes