As it turns out, the issue was with IHG's system. Somehow they created three distinct reservations. When I log on to the IHG site it only shows one. When I looked on the app it showed that I only had one but it also showed me checking in at 2 pm on the day that I was leaving but checking out at 11 am the same day. I don't blame the Venetian, they were just doing as instructed by IHG. Fortunately it was a very light night and the extra two room would have gone empty anyway so no harm no foul other than the two hours of wasted time.