The forums have plenty of requests for this to work:
https://forums.bohemia.net/forums/topic/283810-combat-ops-everon-sp-does-not-save-progress/
https://forums.bohemia.net/forums/topic/283765-combat-ops-everon-broken/
Youtube showcases the problem as well: https://youtu.be/Pn2yIqfOiog?t=1145
This bug causes single player Combat Ops Everon to be far less interesting and thereby removes a large portion of potential gaming hours among the community and Reforger supporters.