When edit mode is entered in https://en.wikiversity.org/wiki/Hilbert_Book_Model_Project/Quaternionic_Field_Equations, then edit mode starts with source editing. Since yesterday switching to visual edit mode splits lines with inline math formulas into lines that hold text and lines that contain math formulas.
This is annoying behavior.
The phenomenon does not occur when source edit mode is exchanged with preview mode or with publishing the document.

I use inline math formulas to discuss variables or short equations.
The behavior is repeating.