How to toggle off disableConcurrentBuilds in multibranch pipeine using scripted syntax

[namraclik]

I previously had this property set in my scripted syntax multibranch pipeline: properties([disableConcurrentBuilds()])

I now want to re-enable concurrent builds for this job. 

I have remove the line above and re-run the job but the 'Do not allow concurrent builds' checkbox remains checked in the job configuration in the UI.

How do I get that option unchecked?