Hello!
That looks like a slight miconfiguration indeed.
When you say "two logical libraries each with two taoe libraries"-does this equal to four logical ones,
or have you simply added one more physical library and now you have 1 logical library per physical device,total 2?
If the same physical exchanger is configured twice in different logical devices and both logical are used in different sessions,the described behaviour may occur.
You might want to configure locknames in the DP's library properties and start with ensuring that only one Multipath library is configured in DP per physical library.