As far as I can tell, the issue first appeared in version 13.0.1 on my Windows 10 (64-bity) OS. I reported it to Wolfram Tech Support in April last year.
For version 13.0.1 the issue persisted in a bitmap export (jpg, png) of a plot, but not in a vector graphic export of the plot e.g. pdf or svg.
The edges of axes disappear if you select another plot, change notebook magnification or when you resize a plot, or when you create multiple plots in one (some plots have no axes on the edges).
