Given the dates Cinch must have been negotiating with the SPFL and Rangers simultaneously. Was this known to all parties, probably not. And there is such a thing as goodwill.
Also we're led to believe Cinch and the SPFL were brought together by a company who specialize in finding sponsorships. Was the purpose of this third party really to subvert commercial confidence, and quite possibly SPFL rules. Wouldn't surprise me.
It's quite possible Cinch broke off negotiations with Rangers after being persuaded a deal with the SPFL was better for their interests. Which would mean that somebody in Cinch, the SPFL, or the specialist company broke commercial confidentiality. It's also possible Rangers broke negotiations off with Cinch because the stadium naming rights deal breached the club's arrangements with Parks. Which again would smack of Cinch having a deal with the SPFL on the back burner in case Rangers didn't sign up.
A stadium naming rights deal, and the SPFL deal are very different. Rangers in negotiations with Cinch, but ultimately not coming to agreement seems perfectly normal to me. However, the third party, Cinch and the SPFL in negotiations at the same time as Cinch were talking to Rangers looks like dirty business to me.