Whatever you did fixed the bug I reported. I noticed one other thing, but it's only noticeable at a low resolution, and not as gameplay effecting so much as visual.
When landing in my example, the platform sprite sometimes land about a pixel or a half pixel into the jumpthru tilebg, but when the platform sprite overlaps another jumpthru tilebg it jumps to the proper elevation. I thought it might be dependent on speed, but I tried raising the values to see if there was a notable difference but it appeared to have no effect on the outcome.
Like I said, that quirk there seems rather low priority, and probably will only effect lo-res retro games like mine and only visually really.
The original bug appears to have been squashed though, so awesome awesome awesome! <img src="smileys/smiley4.gif" border="0" align="middle" />