> not here with current version: 2011.02.25 22:03
> %%test
> \starttext
> \startTEXpage
> \startMPcode
> draw origin-(20,0) .. origin+(0,20) .. origin+(20,0) .. origin+(0,-20) .. cycle;
> label(textext("Test"),origin);
> \stopMPcode
> \stopTEXpage
> \stoptext
>

The problem occures with luatex rev 4088, no problem with 4050 or 4060