So I’ve just done a full run through of the Campaign on Heroic and finished the Epilogue…except I didn’t get anything for completing it on Heroic, so I checked back through my missions and it said that I had only completed Tsavo Highway on Normal. Odd, I thought, so I cleared it again, double checking that I’d completed it on Heroic. It still didn’t save. Something’s very clearly broken here and I’m not at all happy that my efforts are going to waste because of it.
Any way I can fix/work around this or am I gonna have to wait for 343i to fix it?
Nevermind, found a fix: Started Crow’s Nest from Rally Point Charlie and then played through Tsavo Highway from that point onwards. I can only assume the glitch is caused by the game assuming I’m starting Tsavo Highway from a midway point.