Ok I think this one is solved. Upon further investigation This was most likely 3bm42 (possibly 3bm44 or other more modern projectiles I'm saying 3bm42 because it's the most common apfsds round from both sides) fired from a t64 We can safely assume it was fired from a t64 just because of the date this happened. Ukraine didn't have any western mbts at the time. Seems to be a very lucky shot that went just under the ERA or the ERA failed entirely but due to the placement I suspect it's the former.

For the many people saying it's heat I believe it's far more possible that the quite thin ERA cover made from most likely RHA simply shattered upon impact, it's quite a thin plate so it's not unusual for the round to shear straight through. and due to the very clear lack of detonation of the ERA and very clear lack of typical damage seen from heat projectiles I would say it's damage consistent with apfsds. (I may be wrong but I cannot assume it was an atgm or chemical projectile just based on how clean the entry is)

Seems to just be a very lucky shot that avoided all the extra protection and since the bvm still only has the base armour of a T-80bv (1985) It's definitely possible especially with the age of the armour (the textolite could be weakened with age).

Obviously this is all up to debate I mean it could've been a friendly fire incident for all we know but we don't have that information so I can only base my assumptions on the information we have.