I have been converting all of our formulas to the new formula option without any issue. You may need to enclose your formula in single tics.
Ex:
'<a href="/app/site/hosting/scriptlet.nl?script=customscript_flo_sod_showviolation_dets&deploy=1&test=T&type=role&intid=' || {internalid} || '" target="_blank">View Violation Details</a>'