@techroll42:
Another odd question:
So, I was mad at Russia for not retreating his Siberian stacks so I attacked him.
Russia believed that if he didn’t declare war on me (but didn’t retreat) and then on J1 I declared war, attacking the Mongolian territories J1 would’ve been attacking a strict neutral. Is that correct?
Yes, even if Japan attacks a Mongolian territory plus Amur during the same combat phase, the strict neutral rule is activated. The decision to retreat or not won’t effect territory status in this case.