The issue I see with Article 17.3 in application to the wording in the RCAM, is that 17.3 specifically addresses the rights of the steward in fulfilling their duties, not those of a carrier in researching policy, even if that research is in good faith, and leads to a grievance.
When it is necessary for a steward to leave the work area to investigate and adjust grievances or to investigate a specific problem to determine whether to file a grievance, the steward shall request permission from the immediate supervisor, and such request shall not be unreasonably denied.
So I don't, unfortunately, see that there's a question as to whom is being referred to when the RCAM references Article 17.3, as that Article specifically pertains to the rights of a steward. Given that stewards are given some leeway to investigate and file class action grievances, etc., it at least makes a reasonable amount of sense that they would be given more latitude in what they are compensated for and when.
And yes, while stewards accrue Z time, and carriers are paid out via 8127, they're both compensation for the terms of our contractual language. If I'm picking up what you're putting down, some of this revolves around what constitutes an Interview, and when is
that compensable. I'd suspect your representatives are holding that, as Interviews are a direct component of investigating a grievance, and are therefore part of the grievance file (with their own paperwork etc) that a steward submits to the DR or ADR upon finishing the grievance or kicking it to Step 2, that there's enough of a body of interpretive language that it's not applicable to carriers requesting to speak to a steward, but the other way around (Steward speaking to carrier).
If management wants to pay, I think that's just fine and dandy. They're doing what feels like
should be right. But at least, to my eyes, taking each contractual provision in totality, the union reps are
technically right. If there are further articles of the contract, or § in the relevant supporting documents that give a strong argument against that interpretation, it'd change my spot interpretation on that pretty quickly; since it's what feels like should happen, but I just can't find a decent linkage to make it so. (I'm also by no means always correct, but I'd prefer being proven wrong, if it leads to a learning moment... So I can be right next time

Heck, compensating this type of time is something my office has always done, and I'd presumed that was the appropriate response until yesterday. Now I have to play the see no evil/speak no evil game)
And yes, the lake is
far more interesting than most contractual deep dives. (Despite my tendency to engage in the crunchier side of things.) Y'all get some of my eyes time when I've got my bourbon by the fire, or coffee by the water. Cheers!