[metapost] Bug with in-box test alignment

[Sebastiano Vigna]

The following Metapost program

outputtemplate := "%j-%c.mps";

input boxes

beginfig(1);
	circleit.n0(btex $0$ etex);
	drawboxed(n0)
endfig;

bye


generates a circle with a 0 label inside, but the label is not centered (I'm converting the output of Metapost with mptopdf).

This behavior started in two different TeX installations after a recent upgrade. I'd like to know if this is reproducible elsewhere, or if anyone has met already this kind of behavior.

Ciao,

					seba