A solved confusing mesh issue

I finally have an answer to the confusing mesh issue that was bugging me earlier today (and has been troubling and confusing me most of my evening too). After I wrote the issue up Beq Janus was kind enough to pop over to my workshop and have a look at it with me. She helped eliminate a number of possible causes (all of which I'd not thought about) and she also helped me better understand the interplay of bounding box scale and LOD levels. Sadly though we just couldn't get to the bottom of the problem.

Eventually, later on, while trying a few things, I got desperate and copied the "problem" linkset and set it all so it only had a single texture. I meshed it and uploaded the result and the resulting mesh behaved as I'd expect it should! I could place the two mesh, side by side, and watch the 4-face one collapse far too quickly while the 1-face one would collapse at the rate I expected. Both were very different rates.

At this point Beq started asking around various groups, one of which was the Sweet Meshes group (the group that supports Mesh Studio). One of the ideas we were entertaining at this point was that it was a problem with Mesh Studio itself.

Turns out this was the best place to ask as this reply came though:

[13:51] Rey (chinrey): Sorry, just noticed the discussion here. Somebody's got problems with LOD of a 4 face mesh?
[13:51] Rey (chinrey): If so, that's an old, well documented bug
...
[13:52] Rey (chinrey): What happens is that the size along the z axis is ignored when the switch points between the LOD models are calculated

That was it! That was exactly what I was seeing! Given the description of the bug it seemed like there were two workarounds available:

[13:54] Antony Fairport: So if I throw a couple more faces into it that I don't need it should fix it?
[13:54] Antony Fairport: or....
[13:54] Antony Fairport: If I turn the build on its side and mesh it?
[13:54] Rey (chinrey): Yes, those are the two solutions
[13:54] Antony Fairport laughs -- 90deg rotation happening right now.

And that was it! That fixed it. If I took the resulting mesh, turned it upright and set it alongside the the mesh made from the exact same source linksets, only with a different rotation, it behaved!

For anyone who's interested and who, like me, doesn't know of it, here's a discussion about it. It's a very odd one but, now I know, I can always work around it in the future.

Many thanks to both Beq and Rey for their help. I would never have got this solved without them.