I downloaded and installed 1P4Android_20140124.apk earlier today. At the time, I went ahead and hooked it up to dropbox where my 1Password file resides and also logged in to the app for the first time with my main 1P password. I then went on and did some other things, got sidetracked and about 4 hours later returned to 1Password to find that it was completely unlocked and had anyone gotten hold of my phone during that time, would have had access to all my secure data and passwords. Ack!
Phone model: Samsung Galaxy S3 (SGH-I747)
OS version: 4.3
Did you have to login to see secure data?
Also, I tested, that at this point app switching does lock the app as expected.