Problem: exporting from Lightroom

And see:

https://www.mtu.edu/umc/services/websites/writing/characters-avoid/

Dots should be avoided in file names, especially at the end, because the dot is used as a separator between file name and extension. So I'm not surprised that Lightroom doesn't include the dot, it saves you from getting into trouble later, image viewers and web browsers might refuse to display the image.

 Consider naming your files in a different way, with a different character at the end, like a dash.

You can easily bulk rename files with a utility like ReNamer , which can for instance replace the last character in file names with a different character.