It's like talking to a brick wall.
Russian have been targeting fuel depot with precision missile strikes, it's not unreasonable to assume the tank ran out of gas due to fuel shortages or supply lines were cut when it was out-flanked or surrounded by advancing Russian forces.
The idea that Russian special forces sneaking behind enemy lines to drop a grenade in an open-hatched Ukrainian tank is unlikely as the hovering Russian drone overhead would have destroyed all operational covert secrecy and alerted Ukrainians of enemy presence. Too risky.
It's not surprising that moth-balled second-hand Polish donated equipment is prone to equipment or mechanical failure in the field due to poor maintenance history. Equipment break down all the time in the field due to poor maintenance.
Still, there is atleast a dozen plausible factors because one can jump to a ridiculous "deliberate fratricide", when we have zero visual evidence of passengers inside the tank to begin with. For all we know, it could be empty tank.
Yet there is a Russian drone overhead taking that very shot. It's likely infiltrators are telling where Russian artillery and missiles are supposed to fire, such as enemy headquarters, ammo and fuel depots.
Look around the environs of the tank. No tracks to reveal it was retreating or moving forward to indicate it broke while moving. No fire and blast damage around the tank. No smoke. Clear symbols and markings with undisturbed ERA. No indication of any fire damage.
I thought this was a scuttling attempt too until there were online chatter that seems to dispute that.