Job setup:
TestRoot - TestP1 - TestJoin
- TestP2 /

All of the jobs are configurated with parameterized string parameters in pre job and TestRoot, TestP1 and TestP2 uses "Trigger parameterized build on other projects" with file as input.
The TestJoin is configurated with "Block while upstreams are build"

The issue is as follows:
The Jenkins build-in feature works ok and does not execute while jobs are building upstream, but the big problem is that the parameterized trigger kicks off two job executions(or as many as there are parallel upstream) rather than just one.

It has been fine one this server when it was original configurated. At some point I moved some upstreams to join in a separated joiner. It seems that changing of configuration triggered the problem. The "funny" thing is that the problem occurs not only on the job I changed configuration but on all using the this setup.

The test setup mentioned above is created after the problem occured and it still have the problem.

I have updated the plugin to get the latest release, but it did not help on this problem.

This is showstopper for me, as I cannot have more than one job execution due to the fact that I need one joined result of my whole "graph" and then continue further actions based on this..
I have not seen it earlier in my use of the this plugin.