We had 42% possession, meaning we had the ball 42% of the 96+ minutes played.
Our passing accuracy was 52%. That means that 52% of our passes were successful (or found a home as you put it). Where are you getting 21% from? Are you calculating 52% of 42%? That doesn't make any sense since our passing accuracy is not in any way affected by Leicester's possession (58%). We can't pass the ball if we don't have it.