Mods: (not sure if any of these are relevant except maybe the docking_port_alignment_indicator, but I am playing a modded game, so it's possible something is causing trouble) toolbar (by Schreiber) ATM B9 Chatterer MKS/OKS/Umbra Docking port alignment indicator KAX module manager KWRocketry IR mechjeb2 procedural dynamics procedural fairings ship manifest stage recovery station science stockbugfixmodules TAC life support interstellar extended Issue is, however, a repeat of the very same problem I had before without the majority of these mods, but I cannot say which ones for sure, except IR, interstellar, ship manifest, station science, and stage recovery, so they do not seem to be the root of the problem. I am not convinced this is a mod problem. Problem: I had a station already in orbit around the Mun that included 2 docking ports. I docked capsules to each without incident, and undocked one of them and flew it away without incident. Then I docked a lander there for refueling before a Mun landing, but when I select "undock" on the relevant clamp-o-tron, nothing happens; the ship continues to be treated as part of the station. It rotates with the station, all parts and parachutes continue to appear in staging, etc. I cannot select undock again. If I return to KSC or save/reload, the problem persists -- I can select undock again, but the same issue occurs. Interestingly, when I opened the save file to see if it could shed any light on the problem with a mismatched pair of docking ID's or some such, I found that while the functional docking port (the one from which I can detach a capsule) is correctly designated as docker and dockee, the malfunctioning pair has the line "state = docked (same vessel)" on the stationside port instead of listing it as a docker. It would appear as if the lander has somehow lost its identity as a separate vessel. ETA: Note -- in case it is interesting to anyone, the problem was reproducible. I backed out to an earlier save where the station existed, but the ship I docked did not. I created a similar ship, flew it out to rendezvous, and docked, and the same issue occurred.