This is a weird error to be getting on mobile. Did you change where the game was installed after starting your save by any chance?
0.4 has fixed the cause of this error but I feel like this function should never be getting called on mobile(since you can't remove girls from the game).
0.4 releases on Tuesday btw, not sure if an Android version will be available immediately(usually wait for any errors to be found and fixed) since I cannot easily hotfix Android versions.