I've filed a new issue on github:
https://github.com/zevisvei/kindle-r...board/issues/3
In the "Reading timeline" section for a book, fpr should be furthest position.
This can be confirmed by syncing, then checking the values for fpr and lpr. Might not be necessary, but I next close reader-dashboard and the browser and disconnect the kindle. Then I open the book on the kindle and page forward around 10 screens, page back around 5 screens, and exit the book.
Re-connect the kindle to the computer and sync again. fpr should have advances by about 10 screens and lpr by about 5 screens.