Beta 4 0.72 Confirm Battle preview w/ship defeding planet shows negative attack/defense/hitpoints

My two ship fleet attacked a single Drengin ship defending its home world.  The confirm battle window that comes up before the battle viewer showed this, with what looks like 32 bit overflow values for attack/defense/hitpoints:

Sorry to keep posting minor problems like this, but on my system I can't get the game to crash

Edit: I have a saved game that demonstrates the problem.  Just use the fleet next to Drengi (in the upper right of the map) to attack the planet and its defending ship.