bash autocomplete prepending a backlash to envars

Question

Just stood up a CENTOS 7.2.1511 VM and when using autocomplete it is prepending a backslash to the front of the envar:

# ls -l $ROOTDIR [TAB]

# ls -l \$ROOTDIR

How do I turn off that behavior ?

GNU bash, version 4.2.46(1)-release (x86_64-redhat-linux-gnu)

Thanks !