Ryan
I know you said "This is a crude version 0.5 beta" it is remarkable that you have managed to resurrect it to this point but there are issues that may be too deep to fix and it might simply be easier in the long run to open and old one. Get a feel for what's needed then recreate it using the current game because chances are there are other gotchas like this lurking
I opened it up and poked around. The first thing I noticed was all the soft sand reports as clear terrain but the other issue might be too deep to fix.
I started the scenario and advanced a BDRM and it was fired on by a TOW Jeep
We have had trouble with message overwrites in the past but not so much lately and to check that I built a quick scenario with Egyptian BRDM's US Army TOW Jeeps and this is the message shown
Just FYI