In the latest version of Jenkins LTS, if you create a pipeline and make Groovy code that changes to a directory called 'stage', "stage", or '''stage''', it will still try and interpret it to a build stage and expect a name argument. If you go dir 'stage' {}, it will complain that you provided a closure to the name argument of a stage command.

Furthermore (and, I find this even stranger), this Groovy code STILL tries to run stage in the same spot.

//This occurs with 'stage', "stage", or '''stage'''
def STG_DIRECTORY = 'stage'
dir STG_DIRECTORY {
    //Some code
}