When trying to publish PMD analysis results for a maven multi-module project the overall reference build (stated at a build results page) doesn't take into account "Use previous build as reference" checkbox.
TC:

1. Create a job that publishes PMD analysis results for a maven multi-module project
2. Create a successful build (let's call in #N)
3. Set build configuration to use deltas and mark build unstable only if there are new HIGH warnings (i.e. consequent builds without codebase changes should produce successful builds only)
4. Introduce 2 new HIGH warnings and start build ( #(N+1) )
   ER: #(N+1) should become unstable
5. Fix 1 introduced HIGH warning ant start build ( #(N+2) )
   ER: #(N+2) should become successful (since comparing to #(N+1) no new HIGHs were introduced)
   AR: #(N+2) is still unstable; it says its reference build is still #N (while console output prints [PMD] Computing warning deltas based on reference build #(N+1))