Some mod fluids appear to completely fill the tank cart (visually it is full) and report millions of mb of fluid in the tank cart GUI. The volume is variable between fluids and it isn't just by mod as some fluids in a mod behave properly, but not others.

This is just visual as the liquid unloader still only receives 1 bucket when emptying tank. It is also possible to put more than one bucket into the tank despite the tank being visually full and reporting a volume over max. Either by hand or via the GUI. The volume reported does not change, however the amount that can be removed by bucket and fluid unloader is reflective of number of buckets placed into the tank. All the fluids that do not work properly in Tank cart work properly in Iron Tank.

An example is Pneumaticcraft (pneumaticcraft-1.7.10-1.11.16-138-universal). All fluids work as expected except etching acid (yes it has no texture still) which reports a volume of 5,250,048mb.