The master key does not change from 0/1 to 1/1.
I'm actually using encryption through masterkey, and I can see the note well.
I just want to change masterkey 0/1 to 1/1.
I do not know the reason why, but for me the sync status for the MasterKey has always been 0/1 on both desktop and mobile and it has always worked for all clients.
I can only guess that the MasterKey is treated differently to all other records. Regardless, you do not need to worry about this.
Just seen that you have also raised a GitHub Issue and that @laurent has marked it as "High" and for "Desktop", however, as stated above, it also applies to mobile.