Ray Tracing Distance Not Working

The Issue:

 

When setting the ray tracing render distance, anything greater than 12 chunks seems to have no effect.

 

Reproducing the Bug:

(This way is the most obvious.) With a large amount of glass around you, change the ray tracing distance settings. The amount of glass that is affected by ray tracing won't change past 12.

 

Expected Outcome:

More glass blocks should be properly see-through as distance increases.

 

Observed Outcome: 

Past 12, no more glass blocks become transparent.

 

Tests for Different Settings (see the glass blocks in the background):

8 chunks:

 

12 chunks:

 

16 chunks:

 

24 chunks: