Hey Thomas, really sorry about this – there’s a known logout bug in iOS 1.9.1 that’s fixed in 1.9.2 (should be released towards the end of this week or start of next).
We’re also addressing slow login (usually caused by having a long feed) in iOS 1.9.4 – thanks for the feedback!
This is unfortunately a side-effect of how we match up your contacts. We care a lot about privacy, so we don’t store them on our servers. Logging out removes cached Monzo data from your phone, so when you log in again we have no way to know whether a contact is “new”.
We should perhaps show all contacts as “old” (existing) on login – will have a chat with the product team about this
Lots more info on how we match up your contacts to be found in this thread:
Thanks!