Many teams do this... it is pretty common practice around the NHL. Teams like Toronto, Tampa, and Detroit are pretty notorious about it and it doesn't hurt their reputation. All parties know it is just a part of the business.
LOC's cap hit change is 4,973 and salary change is 4,099. Connauton's salary stays the same, but his cap hit change is 5,780. Avs saved 10,753 against the cap by simply waiting until 3pm. Not a ton by that one instance, but if that happens just 10 times during a season... that is 100k in cap room. The Avs are swimming in cap room right now, but that doesn't mean they will be at the end of the season. Right now, if they made a trade for Hall, they'd only be under the cap by about 400k (his remaining cap hit is about 4.7m and Avs have about 5.1 in current room). Then, any changes from there would end up forcing them to LTIR which could reduce the banking that is currently going on.
Just explained in this post. It is about flexibility and maintaining it. They saved 10k in cap room by waiting a couple hours.
On top of all of that, the Avs are very vulnerable to ELC bonuses this year. Almost 3.9 out there on the books that isn't currently counted. Makar is likely to find a way to end up with some of that.