I do also save a scene, but just the "base", then do pose-variations and save just the additional poses, so it is easy to create some sort of "timeline" from one pose to another, without having to load the whole scene every time.
So, generally, there is one scene and x-sum of poses to that. If I do dforce, I usually save that in its own scene.
The part that was "going wrong" with my initial post, was my habit of backing up my render & scene-dirs to an external source every now and then and pulling the latest files from its original network share to be locally available on the daz-machine. I do that with a batch-script mirroring using robocopy or rsync and let that run in the background while having the daz-session, so most of the time, my dirs are in sync.
Problem was, I was not attentive enough. I initially write and load the scene & pose-files to the network-share, and do not have them locally until I sync again. This time, I unfortunately set my net-share as target, and therefore the additional new files were purged. And had also not been backuped, as it was also running ... from the netshare to backup.
Long story concerning no real problems, just five poses and one scene for nothing.