Slash added at the end when refreshing a static page

[freereikicourse]

For example go to: https://www.freereikicourse.com/advanced_practitioner_level_2_12.html

Refresh page.

You will see:

This messes up all the analytics because all pages are duplicates.

Repo is here: https://github.com/freereikicourse/freereikicourse2_build/tree/ae3f351e413dfe1a9f9a07fde6908773dea1e498