If the inventory (in any gamemode) is in its most simple mode (the chest-only icon) when opened, and then switched over to any expanded view (book-and-chest or open-book) pressing L will always select the All category, and pressing R will cycle between All and Nature. (If anything other than All is selected and R is pressed, it will switch to All, if All is selected, it will switch to Nature) Reopening the inventory in an expanded state fixes the issue.

Video showing issue:

https://drive.google.com/file/d/1ViqRPbVgQBt_0ooNuAntK0ejI7hyvhUT/view?usp=drivesdk