Unexpected positional replacement strings substitution

[aero]

Hi,

I try to execute a shell script like the following form.

p.sh

-----script start--------------------------

#!/bin/bash

SCRIPT=$(cat <<'EOF'
# long shell script
echo $1
echo ${1}
EOF
)

parallel -v "ssh {} bash <<'_PARALLEL'
$SCRIPT
_PARALLEL" ::: localhost
-----script end--------------------------

But I encountered an unexpected problem.

GNU parallel silently replaces {1} of shell "${1}" variable with supplied arguement.

RESULT:
$ ./p.sh
ssh localhost bash <<'_PARALLEL'
# long shell script
echo $1
echo $localhost
_PARALLEL

Can I change gnu parallel's postional strings substitution pattern ?

or

How can I avoid this unexpected replacement with any other method or trick ?