Op, are you the one who originally found this?

 

I think he/she is.

 

It's the hearse again.

Maybe it wasn't a mistake...
But it was awful small.

 

I have just re-watched the episode again this morning. It took me 4 attempts to spot it, but just before the biker crew are blown up the car comes into shot. Very well spotted by the OP. At 1st i thought it was an accident. I am now convinced it was negan or another of his crew. Im sure i read somewhere that negan is in this episode but you dont really see him.

 

Like blood on the katana?

 

And the walker drinking bottled water.