Change of Master Password not taking effect - complete confusion

All,

(It's a long post - so please bear with me.)

I have four devices running 1Password:

1. MacBook Pro (work) 10.9.0 1P4 v4.0.5 (405002) - non-MAS
2. MacBookPro (personal) 10.9.0 1P4 v4.0.5 (405002) - non-MAS
3. iPhone 1P v4.3.1 (iOS 7.0.3)
4. iPad 1P v4.3.1 (iOS 7.0.3)

They are all synced using Dropbox. I know that they are syncing correctly as when I make a change on one device - it is replicated to the others. Beautiful.

I decided to change my Master Password on my work MacBook Pro. I watched the Dropbox icon show that it was syncing and let it finish. I then did a bunch more work for a couple of hours and then shutdown my Mac. On my way home I thought I'd see if the change of Master Password had rippled through to my iPhone/iPad (as one of things that I didn't like with the old iOS versions was that you had to change the Master Password separately).

I opened 1P4 on my iPad and typed in the old Master Password to see if it worked - it did! I then let 1P4 on my iPad finishing syncing (by looking at the settings pages) and then quit the app (by double-tapping the home button and flicking the app away). I then started 1P4 on my iPad again and typed in the old Master Password - it still worked!

I then tried the same with my iPhone - and got the same results.

When I got home - mystified - I fired up my home Mac, let Dropbox finish syncing and started 1P4 for Mac and I could still log in using my old Master Password. This definitely wasn't expected behaviour.

I then tried my new Master Password on my iPad, which worked, and then tried the old Master Password which had stopped working. I then did the same on my iPhone and observed the same behaviour. It seemed that by typing in the new Master Password - it could then forget the old one. This was confirmed because now my iPhone and iPad have both stopped accepting the old Master Password.

So lastly I tried my home MBP - which still accepted the old Master Password and refuses to accept the new Master Password.

This definitely isn't expected behaviour. I would expect that one you've changed the Master Password in one place and the devices/MBP has synced - then the Master Password would change in all places.

Agile - can you help, please?

Many thanks - Jonathan.