That could be the case.I think it has to do with what movies are actually being aired during that month. If Rouge one is not being aired on any channels in the month of June then it isn't free. I found that same thing with other movies like Jurassic Park. There's been times where Jurassic World was free but the original Jurassic Park wasn't.
I like Rogue one. Better then force awakens.It sounds cheezy like just about anything else that has "warfare" in it's title.
I was in the mood to watch Rogue One but oddly,OnDemand only has Solo and The Last Jedi currently.Both are newer than Rogue One so no idea why it isn't offered along with them.