Oslo-RYG appear to have been dropped.
Last I heard Ryanair was in dispute with Rygge over planned tax increases and was threatening total withdrawal from that airport effective October. Things may change if an accommodation can be reached? Meanwhile, Ryanair is reportedly considering a move to Gardemoen.
Having said that, I never booked MAN-RYG despite attractive fare offers because the flights arrive there around midnight and RYG is a long way from town. The service was more suited to Norwegian residents with cars / lifts available locally. Of course, somewhere has to have a last-rotation-of-the-day flight. In this case it was MAN.