Your screenshot looks more like Notepad++ thinks the font’s width is different than the font actually displays, so the cursor ends up farther to the right than the actual text is.
What are your settings in Preferences > Style Configurator > Global Styles for the Style: Default Style and Global Override (show a screenshot for each)?
You might want to try changing the Default Style to Courier New or Consolas, at least temporarily, to see if it still has the mismatch between cursor and where the text actually is.
(I personally use the freeware Deja Vu Sans Mono as my monospace font for Notepad++ and similar, as I think it looks good, and it has fairly good Unicode coverage built into that font.)