No, SwiftKey works flawlessly on mine. I guess that's because the possession issue from your storage. I ever had that issue, and it needed to wipe the internal storage first.
So i frequently go into the official english miui forum and visit the "unlock the bootloader" thread to see what's going on, and try to help others that may not as luck as me to unlocked my device easily without any big deals. The confirmation came in time and i can immediately unlocked my phone...