I have found a very simple fix for this!
1). Open Settings>General>Keyboard
2). Delete the keyboard shortcuts that you do not want
3). Go back and open Settings>General>Reset
4). Select 'Reset Network Settings' (you will not lose any data but you will have to re-enter your wifi password)
5). After this, I did a backup too but it isn't necessary
It has been 24 hours since I have deleted the shortcuts and they have not comeback. (Used to come back after 15 minutes so I think its safe to say it's fixed)
This issue has really been annoying me for a long while now so I hope this fixes it for you🙂