When I put the unnamed items (leash/hayball) into my hotbar, the numbers for itemcounts would either flicker (the white part of the number and the exp bar as a whole would vanish for a few frames) or they would change color to green, blue or red for a few frames. I'm running at about 60 fps, with normal render distance (tiny render distance seems to reduce flickering, but not totally get rid of it)
Never ever had similar grafical issues with Minecraft.