understanding milestone and locks - why is stage terminated?

[Torsten Reinhard]

Hi,

I have a large development pipeline doing the Build, Deploy & Test of some MicroServices. Reduced to the essential parts it looks like:

node() {
    stage ("CI: Build, unit test") {
        milestone label: 'Building...'
        ciBuildTest( ... )
    }

    // Lock running SonarQube - the newest build waiting for this lock will get it, first
    // => old builds should be skipped to save time
    lock( resource:"${myProject}-SonarQube", inversePrecedence: true) {
        stageCiAnalysis( ... )
        milestone label: 'SonarQube analyzed'
    }
   
    // Lock using the environment - the newest build waiting for this lock will get it, first
    // => old builds should be skipped to save time
    lock(resource:"${myProject}-${ENVIRONMENT}", inversePrecedence: true) {
        migrateDatabase (...)
        deployToServer(...)
        smokeTest(...)
       
        milestone label: "${config.environment} deployed and tested"
    }
}

The intention is that parallel buils are created even when an older build is being analyzed by SonarQube or if it will is being deployed and tested - and if the (deployment) lock is released, the newest build (LIFO) should be used for the next deployment.

When running that pipeline, I detected the "deployToServer" stage being interrupted - although it´s part of a lock that hasn´t been released:

2017-09-12 16:38:27,208 [main] INFO  LogOutputHandler deploying.......

Superseded by DEV/MRPCLASSIC/DEV_MRPCLASSIC_DEVELOPMENT#548
Sending interrupt signal to process
[Pipeline] }
[Pipeline] // stage
[Pipeline] }
Lock released on resource [DEV-MRP-EMEA-TEST]

Why does Build #548 send an interrupt signal to #547 that is being executed - and inside a lock? 

Whats´missing here?

thanx for any advice, 

best regards, Torsten