Direct hits are not required to damage vehicles. Large calibers produce a lot of heavy fragments whic hremain damaging to armor from 10+ meters away. You just need a lot of dice rolls and one of them will fail.
Soviet HE mortar ammo came in two main flavors: FRAG-HE and HE
FRAG-HE has a thick steel case, much like an artillery round, and is designed to produce fragments. M795 155mm round has around 25 lbs of explosive filler.
HE has a thin steel shell and functions through blast effect. The 160mm mortar round has about 70 lbs of explosive filler. Mortars can throw more explosive, being a low pressure cannon. The case need not be so thick.
Now, 70 lbs of explosive is quite a bit. Target effects of a near miss include knocking the vehicle on its side; stripping hatch/cupola, externally mounted weapons, sights, and comms; blunt force trauma to crew (from banging into steel when the vehicle is knocked about); spalling of the armor (spall liners generally protect crew, but not automotive components, like the engine); and external automotive damage (broken track, suspension damage, side skirts warped and interfering with track, etc)
Even without seeing the numbers for this example, I'd expect broken tanks.
Saw a pic of a Leo 2A4 hit by Syrian arty (likely 152mm) on the turret roof. Tank did not catch fire and all crew survived, bit it needs the turret completely replaced. Turret crew was wounded by spall. Driver unhurt. Turret roof caved in a goodly bit.