Having an odd issue with dialog profiles, if I try to set/check profile based on $fU or $rU call is always rejected due to call limit, but $ru or $fu work without an issue.

Example using $fU-

$avp(s:checkuser) = $fU;

set_dlg_profile("quota","$avp(s:checkuser)");

dlg_manage();

get_profile_size("quota","$avp(s:checkuser)","$avp(s:calls)");

       avp_db_load("$avp(s:checkuser)/username", "$avp(s:callquota)");

       if ($avp(s:calls) <= $avp(s:callquota))

…….

If I change checkuser to $avp(s:checkuser) = $fu; it returns the correct result.

Any explanation for why this is?