Odd TB Truck situation

[Wiedrock]

I don't know why/what exactly that is related to. But inside TBs the Units (at least some) seem to stack/keep their vehicle pools altough they are not/no longer needed.
I assume it has to do with an TOE change in general and more specific a change of Motorization status between the TOEs while the unit is inside the TB.
This is an older game and some TOEs since then have changed in their Motorization status I think, so it may look different for some now.