When you change the master password of Enpass on any of your devices, it will get changed on all the devices after successful sync with the cloud.
First, it is changed for the local database on the device from which the change was triggered and then the change is reflected in the cloud after the next sync. But the new password won’t be automatically updated on the rest of the devices because they are not aware of the new password and will still unlock with the older one.
And during the next sync attempt, the other devices will fetch data from the cloud (which is now encrypted with a new password), but won’t be able to sync and will end up with a sync error. You will get a prompt to provide the new master password of Enpass data in the cloud, and right after entering the new password, the master password will be updated on the device, and the sync will also get resumed.