"IVP Failed" when trying to blow up armored vehicle

So I’m about to complete “Surface tension” (thanks for quickly resolving the walking on pipes/ledges bug, btw - great job) but nearly each time the rocket hits armored vehicle in bm_c2a5f, the following dialog is shown and the game quits.

Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.