That is most certainly NOT collusion.
If one team offered you a $5m and a mid-level IFA signee for last year's 2nd round pick, and another team offered you $3m and a tryout camp signee for the same player, and you took the SECOND offer THAT WOULD BE COLLUSION. But, if two teams offer you the exact same deal (which is what you describe), you can accept whichever you want for whatever reason you want, and that's NOT collusion. That's just doing business in the real world, where personalities and personal preferences do matter.