I did a complete reinstall of GWX 3, without installing SH3Cmdr.
Began a campaign in 2nd flotilla. I made several saves, with no sinking ships and with some after sinking 2 enemy ships.
Well, exactly the same issue : save game crash if i load the one in which i sunk targets.
The game saved before shooting load fine

So, in my install, it's not SH3Cmdr problem. I will investigate with the mods i have installed, it takes time

but it's weird because it's the few mods i was using in the past and all was ok.