I have a build job that polls Perforce for changes every 5 minutes. Occasionally, with (seemingly) no changes, Jenkins still start building the project every time it polls, regardless of whether there are new checkins or not. I call this "runaway polling".

If I disable the build and then re-enable it after everything has finished, the runaway polling stops. However, this quickly overwhelms our Jenkins instance, as we allow concurrent builds.

In the Perforce polling log, this message correlates to the problem. I see it in every "runaway polling" build:

no polling baseline in D:\workspace\jobName on NODE_NAME
Done. Took 7.2 sec
Changes found

Neither the node nor its p4 client are new, both have been in place for days. There's no indication what command is being run to check the "baseline", nor is there any information on why it starts failing, so this is very difficult to troubleshoot.