- (With "Manually add spaces" off) You can first try Settings → General → Fix automatic detection. Follow the guide at right hand side to acquire a suggested value.
- If this does not work for you, turn on "Manually add spaces". Then add your spaces manually. Notice, if new spaces that are not in the saved list appear, they will all be marked as "Fullscreen". You can add them as spaces in the settings again.
Demonstration on how you can fix the automatic space detection: