Neon won't allow you to create an oblique bigger than a fifth

The normal behaviour for creating an oblique is as follows:
- Select two consecutive puncta with the neume component tool;
- Click on "toggle ligature";
- The two puncta become an oblique;
- The end.

However, I've just come across an oblique that covers an interval of a sixth and I'm having some problems. Here's how to reproduce that:
- Input two new puncta that are at least 6 notes apart, and group them with the neume and neume component tools;
- Select the two neume components and click on "toggle ligature";
- No oblique will appear. Instead, the lower punctum should hop to align vertically with the upper one. If you move either puncta around, the other will hop up one pitch.
Here's a demo:

https://user-images.githubusercontent.com/83373378/225623422-cd0a4895-f27d-4576-927c-edb9322227e4.mov

Additional fact: in the MEI file, the two neume components are ligated. They just don't show up as such in Neon.

This bug is very uncommon (I'd never seen such a long oblique before), but when it happens I have no way to work around it.