Mode shortcuts are not correctly restored on startup

I'd like to change the keyboard shortcuts for switching between different modes i.e. edit, design, debug, and project. I set my preferred keyboard shortcuts through `Tools` -> `Options` -> `Environment` -> `Keyboard` tab. I then apply the changes and close the Option window. The shortcuts work properly. I check the `QtCreator.ini` file and confirm that they are saved under `[KeyboardShortcuts]` category as:

QtCreator.Mode.Design=Ctrl+1
QtCreator.Mode.Edit=Ctrl+`
QtCreator.Mode.Mode.Debug=Ctrl+2
QtCreator.Mode.Project=Ctrl+3

Now, I close Qt Creator and check the `QtCreator.ini` again and confirm that the newly modified shortcuts are still there. However, when I run Qt Creator again, it changes the `QtCreator.ini` and removes two of my shortcuts. This is what it has now:

QtCreator.Mode.Design=Ctrl+1
QtCreator.Mode.Edit=Ctrl+`

I repeated this process couple of times with no luck. How can I fix this? Is this a bug?

(I am using Qt Creator 4.5.2 in Linux.)