Halo Reach System Link Problems

Ok. So I used to get a group of friends together once a month all the time and system link Halo Reach on a LAN network and we would play for hours (Multiple xbox’s, I collected and repaired. I had 12 total.)
Anyways, current day issue. I have two of my xbox’s with the absolute newest system update available for download from the xbox itself over wifi.
The games still refuse to system link even though I can do it with Halo 3 multiplayer (3 and ODST) and Borderlands 2 with no issues at all.
Now I tried linking Anniversary edition to Reach from one of them to the other and it would let them link, but when I switched the games around in the xboxs they wouldn’t link. I have NO IDEA what to do. I found a download for a title update but it doesn’t bring up any option to install it when I put it in the xbox.
Any advice or help is definitely appreciated, I’m losing my mind. I have nothing else I know to try. I don’t understand how they would just suddenly become incompatible.