Halo4&2 mission completed in coop when done solo?

This has probably been mentioned many times before, about stats saying not all mission have been completed, but I just finished Halo 4 on legendary and was wondering why it was claiming i had been playing some co-op and not all solo.

I went onto career>halo4>campaign stats and its says I completed 6 missions solo and 4 co-op. First this is impossible as I have not played with anyone, also on mission select they all show completed solo and legendary and all say co-op is unplayed.

I know people have had trouble with missions, saying not completed (like i have finished halo 2 legendary but says only 9/10 mission completed.), but I thought this was very confusing as its says 10/10 completed, just somehow not all on solo.

If anyone else is having this problem and knows whether its a bug or something else related to online competitive scoring and timing, I would be really grateful for any info or help.

Thanks

It’s gotta be a bug, I’m having the same problem. I just beat Halo 4 by myself and it says 3 levels were done co-op… Which is weird because my game says they’re all done Solo and this website says 3 were done co-op and i haven’t played halo 4 with anyone