When shooting HE shotShell projectiles through trees they create full scale explosions that do no damage. These explosions trigger HitPart on the shell, HitPart on vehicles nearby but no HandleDamage so explosions are mostly effects and semi-false event triggers.
Same doesn't happen with 40mm GMG shotShell grenades though, I couldn't figure out why exactly.
All in all, tank shells shouldn't explode 20 times during flight, even if its just effects.