I don't really know what happened with GT Inperial Navy. SJG agreed an outline and issued a contract, and we wrote a draft to meet the contract deadline. We sent it in and they alternately went quiet for ages (ignoring our requests for updates) then demanded to know where the manuscript was.
Each time we told them they had it, and had been in possession for a good while, they then went quiet for months before a different editor contacted us and asid he'd been given the project and where was the manuscript?
This went on for years.
Some time later Loren offered me a personal apology for the messing-about, even though it was not his fault. I never found out exactly what happened, other than the vague suggestion that Steve Jackson or someone high up wasn't keen on the navy model we'd used (shame that, because we based it on the official traveller universe writeup of the Imperial Navy, ie Traveller canon).
They never had the courtesy* to tell us what their issues with the manuscript were, nor actually that they had issues. Just long silences followed by demands for information on a manuscript they already had. We prodded occasionally over several years and finally gave up in the face of a good hard ignoring from everyone at SJG.
I've not worked with SJG since.
* except for Loren personally feeing bad about something that wasn't his doing.