WARNING: Spoilers for Thor: Ragnarok and Avengers: Infinity War below.
Calling out plotholes is a risky business these days, mostly because a lot of the alleged holes aren’t really qualified for the title. This particular aspect of the Thor films and their relation to Avengers: Infinity War might not be a plothole at the end of the day. It might not be something that needs fixing in the story of the Marvel Cinematic Universe, much like aspects from the early films that aren’t around at this point — Edward Norton’s take on The Hulk for example.
That doesn’t mean fans aren’t going to have some fun with what is happening on the screen, and fun is all it is at the end of the day. Sometimes fans expanding ideas hinted in the films can be interesting, and it doesn’t hurt that this one makes a lot of sense when it comes to the Infinity Stones and the Marvel Cinematic Universe. Spoilers ahead!