Unable to play non-spec ops mission (from completed region)

I can't seem to replay old timely missions in a previously completed region, even if my stamina is full at 100.
The Objectives is there and all except I can't click the play button. (seemed disabled)
For example, I am in region 2, but you can go back to region 1 and have access to the spec ops and the non-spec ops mission. The spec ops you can play just fine, but the non-spec - the play option seem disabled??!
It's a waste if you can't play it.
Anyone here getting the same thing?