Beaver and Weasel are usually tied to connection instability between you and Bungie’s servers. If you’re playing old Destiny 1 (Vanilla), the servers are super sensitive now, and even minor NAT issues or strict firewall settings can cause constant drops. If you're on the same network, try switching one of you to a different NAT type (like one on Wi-Fi, one wired) or even use a mobile hotspot temporarily to test if that helps. Also, make sure UPnP is enabled on your router. Unfortunately, Bungie doesn’t actively support D1 anymore, so there's no real fix, but tweaking your setup might reduce the errors enough to play smoothly.