So, some assorted comments.
1) Good, old David Mayhew wrote a classic, from 1974. Congress: The Electoral Connection. Basically, electorally-motivated Members of Congress engage in three main types of behaviors: advertising (self-promotion that includes more than just running ads), credit-claiming (getting pork for your district) and position-taking. That last one is the vital one here. Do a lot of stuff that isn't actually about shaping policy, but instead is about taking a public position that will be electorally beneficial. When the GOP could count on anti-Obamacare votes to be futile, they were happy to cast them. Now, they're scared. Plenty of people have commented on it, including, at one point, Sean Spicer! McConnell wants people on the record when there are policy stakes based on the premise that past promises will constrain them, or at least shame them. Note that those past promises aren't. See, for example, Capito. Why? Because position-taking votes are bullshit. Now that it matters, Senators are acting differently. When policy is on the line, and Senators know it, they take that into consideration. Should we really expect otherwise?
2) Weird quirk of Senate rules: Anyone who votes no on a bill can bring the bill up for a vote again. So, Senate Majority Leaders will often vote no on bills they support because they don't have the votes now, but think they might later. Watch what McConnell does. Suppose he gets enough votes for a motion to proceed, but whatever bill there is goes down. If he votes yes, he is admitting defeat because he isn't casting the vote that will allow him to bring the bill up for another vote later. He is, instead, casting the "position-taking" vote, a la Mayhew. On the other hand, if he votes no, he is casting the strategic vote that will allow him to try again later, thinking he might be able to get it done later.
3) The thing about 2 is that most of the time, other actors understand Senate rules and don't get in a Majority Leader's face when they cast a strategic no vote to exploit that rule. What happens, though, if our fucking idiot Tweeter-in-Chief sees it happen, doesn't understand it, tweets something about how McConnell is a traitor who should be dragged out into the street and flayed alive, and then won't back down once it is explained to him because Trump never backs down and always pretends to have understood everything, even when it is clear that he is just a fucking moron who reacts based on no knowledge whatsoever? Just a thought....
4) This is all pointless. McConnell doesn't have the votes and he knows it. Stop stepping on those rakes, Mitch!