The locks-and-latches plugin fails to lock each slave when running a matrix job
running on several slaves. Instead, the job is run on each slave in parallel.

Stephen Connolly has posted these follow ups on the mailing list:

"I think the other issue is a bug in ResourceLists in the core of
Hudson. I'll write a unit test to check my theory and maybe commit
the fix. I have a work-around in the Locks and Latches plugin that
should detect when the bug is fixed in the core and disable it's
workaround!"

"I have filed an issue and checked-in JUnit tests with regards to the
resources issue:

https://hudson.dev.java.net/issues/show_bug.cgi?id=1080

When these are fixed that might fix the matrix issue. The RFE may
still need some work, if somebody can raise the RFE that way I'll
remember to get back to it when the core is fixed.

-Stephen"