McGinnis has a modeling problem in his right armpit.

[砂糖菓子]

It can be seen in the actual game and a small animation posted by a valve animator.

 

[BedlessSleeper]

All the models are placeholder / expected to be finalised much later. Also not a bug.

 

[Archival]

All the models are placeholder / expected to be finalised much later. Also not a bug.

Pretty sure thats for valve Q/A to decide, just because something isn't a programming issue doesn't mean its not a bug.