Me too.
The thing that worries me, btw, is that in the save editor, when you choose "mech", the PXH-1b is the only one that's not there! The list includes all mechs, except it. This could have something to do with the fact that it's the only mech I wasn't able to find? Makes me think.
In the same way, if I add only the mechparts (2, not 3, to avoid the known issues about it), once I load the save I'm not able to get into the mechbay. Weird.
And, again, the fact that it happens only with the PXH-1b maybe it's just a coincidence, maybe not.