Comment 4 for bug 654192

Yes and screenshot is needed for debugging these issues, as because of the Hinting there can be quite alot of potential variance in rendering (hinting enabled, what DPI, what exact pixels-per-em) and of course, the exact size that is showing the issue!

I've spent an hour or so playing with these, depending on the style and weight the cut-line height use between the Н and Њ; the bowl height is also slightly different between Ь and Њ (one has been moved up, and one has been moved down as a compromise). I assume what is happening here is as the size reduces hinting has to eventually make a decision about whether to nudge the cut-line up 0.5 pixel lines, or 0.5 pixels lines; and the choices made differ.

It might be possible to cure this with hinting alone, but possibly it might warrant some tweaking to fundementally bring the cut-line and bowl height closer. I'll ask DM to have a look at this later in the development cycle about this.