Bug, exploit, or just a game mechanic?

So, just wanted to get some clarification with Epoch as a mod and some of the bugs people have seen. I had two of the @mas vehicles stored at my base, which was completely locked/secured. I logged in today and found that one of them had gone missing (of course the one that stored a majority of our equipment). Both were found same time frame, and have been present through multiple resets. Has anyone else had vehicles vanish or could this be someone using an exploit to move vehicles through different objects.