slideshow (gift box) prepends wrong stuff to URL

[brianmapes]

Expected:

Gift box (slide show) SHOULD do this:
https://nbviewer.org/format/slides/github/MPOcanes/MPO624_2022/blob/main/Notebooks/Tropycal_package_BergLillo.ipynb

Actual behavior:
https://nbviewer.org/github/MPOcanes/MPO624_2022/blob/main/Notebooks/slides/github/MPOcanes/MPO624_2022/blob/main/Notebooks/Tropycal_package_BergLillo.ipynb

which is a 404 error

Github address is
https://github.com/MPOcanes/MPO624_2022/blob/main/Notebooks/Tropycal_package_BergLillo.ipynb

Open in nbviewer extension adjusts that to
https://nbviewer.org/github/MPOcanes/MPO624_2022/blob/main/Notebooks/Tropycal_package_BergLillo.ipynb