"Externally Modified" warning when saving file opened from symlink

Version: Mousepad 0.5.3, Xubuntu 21.04. Steps to reproduce:

touch original.txt
ln -s original.txt symlink.txt
mousepad symlink.txt

Add some content to the file, then try to save. You will get a warning dialog that says "Externally Modified The document has been externally modified. Do you want to continue saving? If you save the content, all of the external changes will be lost. Cancel/Save As/Save"

This behaviour did not happen with the previous version of Mousepad (0.4.2 in Ubuntu 20.10). If you run mousepad original.txt and save changes, it saves as normal without a warning. Not a serious problem, but it does get quite annoying being prompted every time, especially as the default is 'Cancel' rather than 'Save', so I can't just hit <Enter> to save.