Monster Hunter Portable 3rd (HD Ver. or not)

[Mysf1t]

Hi,
I'm having a really bizarre issue running this game and I'm hoping for some insight. I'm running this over Evolve, primarily. I tried it with Tunngle too and the result was the same. All of the networking and port forwarding is running smoothly. The latency between myself and the other person in my network is pretty reasonable, no higher than 100ms at any given moment. We're both able to access the guild hall together. The issue comes in with posting quests. When I post quests and we load in together (alternate speed: 25), it triggers almost right away and everything is fine. When my friend posts a quest and we load in, we're left to sit at the loading screen for significantly longer and eventually everything drops. I've double and triple checked everything I can think of so far and can't find the problem. Any ideas?