Run the game up with NO mods enabled. You should see version 2.0.2 5e2f in the launcher, the main game screen, and in the MP screens. If you see anything else in any one of those places you have a bad installation:
- move any valued save games elsewhere, and user_empire_designs.txt from /Documents/Paradox Interactive/Stellaris/ if you have made any custom empires or races.
- "uninstall" in Steam-Stellaris
- manually delete both the Steam/SteamApps/common/Stellaris AND Documents/Paradox/Stellaris folders
- re-install game in Steam, run a Steam Verify when done.
- start the game with no mods active and test
In particular you need to make sure there are no files or folders left under either the Steam Stellaris or Documents Stellaris locations, before installing again.
If the version is the same in all three places unmodded, but not when mods are loaded, you have different mods or different mod versions than the other players.