I see this on Windows 11 Pro, Anki version 2.1.54 (b6a7760c), Python 3.9.7 Qt 5.15.2 PyQt 5.15.5.
When adding a cloze deletion via the shortcut ctrl-shift-c, standard behaviour is that, if nothing is selected, the cursor ends up inside the created template. That is, we get {{c1::x}} with x the cursor position.
This still works fine when typing in the normal text input. However, inside the Mathjax live preview, the cursor is instead placed after the template. That is, pressing ctrl-shift-c with nothing selected gives {{c1::}}x.
The behaviour when something is selected is instead consistent between normal text and Mathjax live preview.
Apologies if this was already reported. I looked a bit on the forum but didn’t find any mention of this.