Dan,
Sorry about the CAPS first post n all.
WED can be a bit contrary to say the least.
Recently built a near perfect cylinder by way of
making a model in Wings 3D and MDL'ed it into WED.
Then traced and shaped over the imported model with blocks in WED.
Did a full build and was getting a error W010 vertex out of plain, Not to much of a problem says the manual?
But it just did not want to build, and I gave up with it.
In saying that I have just rebuilt the MAP just to get the error code to tell you.
Guess what it built with no errors at all.(This was just a model with no sky box).
Also when it started throwing up errors block 52 vertex out of plain,it was grouped.
So I ungrouped the whole model/cylinder.
When selecting every individual segment,They all came up as block 52 independently.
That may be because I don't think I rebuilt after breaking the model up?
WED ? Seems to hang onto memory or it's own way of thinking sometimes and goes for the shortest route which isn't necessarilly the last thing you input.
An example, building MAP entities seem to disappear sometimes but they are there.
In the past I have found closing and reloading WED can help.
Well Dan you know more about this than I ever will
but it might help someone.