I'm not sure if this is recent or not but I have found an incompatibility between Space Exploration Stuff and Cargo Ships.

When Space Exploration Stuff is installed the Ports can no longer be placed against the Waterways but can now be placed against normal Tracks.

I'm also posting this in the Space Exploration Stuff mod discussion as I am not sure which mod needs the tweak.

Yeah, it's the other mod's fault. Literally right there. https://github.com/rekales/Space-Exploration-Stuff/blob/master/prototypes/space_train_stop.lua

SE Stuff mod dev here.
Yep, my fault. I will add an incompatibility while I try to resolve it on my side.

@krei_ do you know if it is already resolved?

Looks like the code is still the same. The resolution should be to add "port" and "ltn-port" to the list of entities that are skipped.

Looks like the code is still the same. The resolution should be to add "port" and "ltn-port" to the list of entities that are skipped.

still broken

After IAMEPSIL0N brought this to my attention, I've patched this on my fork of Space Exploration Stuff here: https://mods.factorio.com/mod/space-exploration-stuff-k2-patch

Ports are still placeable next to normal rail track as well, unfortunately, but this was a pretty hasty fix for me and I'll be traveling for a bit. I may try to debug it later. If someone else comes up with a solution in the mean time, I'll make time to add it to a release.