@foone Can I ask what font, OS, and LibreOffice version this is? I did a lot of research on this in the past and contributed to bug reports at the Document Foundation about the issue.
This looks like a failure to use subpixel positioning on the glyphs, so the position of the 'a' glyph is rounded to the nearest glyph and looks very weird. LibreOffice switched to using subpixel positioning for all rendering with version 7.4, but I could imagine this happening with weird font / hinting settings.
@foone Maybe you also changed your zoom level or font size? The revised text is quite a bit larger (when you reverse the upscaling on the original image).
I'm curious whether, at the same size, the shape of the 'c' glyph is as cursed as it is in the before image. I can't think of any LibreOffice bug that might cause that, although they've done some strange things on Windows in the past IIRC.