Sorry, in my earlier response I confused this post with another one (Client intermittently fails to open bucket or connect to a node during bootstrap)
I can easily reproduce this issue, but it does not require anything special (like extra/heavy CPU load that I mentioned in my last post).
As I noted earlier, I have 3 buckets and each has a password configured. When the 2nd bucket (in the list of buckets) has an invalid password configured, then the attempt to connect to the 3rd bucket fails as well.
Would it help you if I enable additional Couchbase Client logs (FINER or FINEST level), and capture that for you?