The way these things usually go is someone finds a "technical" loophole or language conflict in the contract.
It might even warrant a grievance or visit to the system board
At that point, both sides submit the negotiator's notes from both sides to establish what the actual intent of the language was. 99 times out of 100 that's the end of it.
Every once in a while, one slips through, where the notes are silent or really vague, and the board or arbitrator actually rules on the extant language.
I seem to remember the AT guys won a major arbitration about their reserve system along these lines...and it caused a major, major shift in how reserved worked for them and cost the company a bundle in pay and staffing.
Despite what people say, language and context matter...a lot.
Nu