f3+g "show chunkborders enabled" does not show chunkborders

Reduced debug info is still enabled, if not with the setting, it's the game rule. Borders are not shown with reduced info, just like a bunch of text in the debug menu (which is enabled, and said text hidden).

Also, only report issues with unmodded launcher, client and server (you have optifine installed, making your reports invalid).

sorry