Hello,
RogueLite was updated today to fix an error that would cause some optional party members to become "stuck" in the party or become unavailable to use.
If you run into any other problems, feel free to email me at Jkweath@gmail.com.
Roguelite update for January 23, 2019
1-23-19 Bugfix
View all patches · Build 3495937 · Last edited March 15, 2019 – 16:59:44 UTC by 
Wendy
Patchnotes via 
Steam Community