The Stable MIUI 8 for Xiaomi Mi series and Redmi series has been pushed to users recently, but there is still a few exceptional models, like Redmi Note 3, which still runs on MIUI whose core is not Android 6.0 yet. Fortunately, now the Public Beta MIUI on top of Android 6.0 for Redmi Note 3 is finally available with version code MIUI 6.9.9.
Known Issue: Those Redmi Note 3 now running MIUI 6.8.18 and having second space feature probably can’t be normally used if OTA to MIUI 6.9.9.
Solution: Delete the already existed second space, and create new second space. Then it will work.