Steve I don't think something "just happened along the way". The substrate for the first element was not annealed well. I have no doubt the astigmatism would have been visible at the time of fabrication, they must have just passed it as meeting spec I suspect. Note that in the absence of the internal strain, the lens would have been excellent with a smooth, well corrected wavefront.
For most, the astigmatism would probably be lost in the seeing. Roger Ceragioli did mention to me that for most coma corrected objectives the astigmatism can be collimated out by tilting the lens. Perhaps this is the case with this objective.
Anyway you can tell, I think, that I am not bent out of shape by a less than perfect lens, even if it is made by Zeiss. They were't perfect, as the link to a Zeiss MakCass in Bratislav's post made clear.
The next step with the optics is to better characterize the mirrors, they are not as flat as could be. I'm inclined not to touch any of the optics and preserve the pedigree.
To let the cat out of the bag, I have an 8" f/15 semi-apo triplet designed and made for me by Roger that I plan to adapt to the Zeiss mount. I'm inclined to replace the two original Pyrex type mirrors with a fused quartz coated with a non metallic multi-layer dielectric coating by Spectrum Thin Films. It's the same coating as used in the TeleVue diagonals. It's optimized for 45 degrees and apparently lasts for ever according to Tony Pirerra, owner of Spectrum Thin films and an astronomy enthusiast.
The original dome that we purchased with the Zeiss is being refurbished and a new, square base is being fabricated. In the new arrangement the center of motion of the telescope mount will be at the center of curvature of the 3m Observa-Dome, allowing for the longer 8" tube to swing around unfettered.