The provided pack has an invalid pack.mcmeta - the format of the field `bidirectional` is not a string but rather a bool and should therefore be stripped of any quotation marks.
This never worked, but previously the error would be hidden (and a default value used instead) - now the error instead causes the data to be rejected and reported to your log file.
When dragging the sliders, the new values would be applied instantly, leading to the graphics settings being applied multiple times in rapid succession. This was causing a repetitive flashing behavior that could trigger photosensitive epilepsy for some players.
We have now changed the behavior so that the graphics settings are updated after a 600 millisecond delay when dragging the slider to a new value, which effectively eliminates any repeat flashes while dragging the slider. The single flash is still present when the graphics settings are updated, but players should no longer experience the repeating flashes that was present before this change.
To avoid seeing the graphics settings being updated in real-time, players can activate the Programmer Art data pack under Settings.
Would be possible to upload the world anywhere so we can test it?