Skill disappearing from skill bar when loading into a new area

https://imgur.com/a/WYL0VOI

I did some more testing and I have discovered some strange things:

I have 149 int

1. This bug only occurs with a level 19 despair (requires 147 int)

2. It works fine if I use a level 18 despair (requires 137 int)

3. It also works fine if I get 10 more int for a total of 159 int

I think the game thinks the level 19 despair is level 20 for some reason? I can cast it just fine at 149 int, but when I go through a loading screen it disappears as shown in the video.