How would you address this with your partner?

[MD Longhorn]

It amazes me how many umpires out there don't understand that the word malicious comes from the word MALICE. Hard contact is not necessarily malicious, in fact --- you can knock someone "into the cheap seats" and not have it be malice (just as you can have a far lesser collision and HAVE MC). Malice implies intent.

First mistake here as mentioned above - there's no such thing as almost malicious. Either there was malice or there was not. There's no warning here.

Second - and worse - mistake. PU should have minded his own business. If this happens to me as BU, I immediately go talk it over with him. I suppose it's possible he saw something I didn't, like a punch attempt I was blocked from... but this isn't likely. This is NOT his call and you already made the call. YOUR call is the one that stands. BU looks like an idiot here, but it was PU who was most likely the idiot.