Master password on iPad different than on my iPhone!!!

Thanks for your reply, but let me try to explain what happened more. Both devices were working fine together with the same password syncing together and without the mentioned problem, this problem happened automatically without adding an account because it was already added and working, but after changing the master password with few hours. I tried adding “Add Existing account” on the iPad as it’s the older password as to make them the same, but it replied that this account already exists.
I would like to mention that this is a family account, I’m the main member or admin and this is happening to my wife’s vaults. I don’t know if this info is important or not.

Please help me on how to fix this, Thanks again