doDownfall game rule appears broken in 1.9

Beginning within the past week, weather occurs spontaneously in 1.9 even when I have specified that it be turned off. For the first three weeks after I updated, this did not happen, and it did not happen in 1.7 or 1.8.

1.9.jar and 1.9.json are both dated 2/29/2016. There are folders within 1.9.jar that are updated today, but no files within 1.9.jar have been updated since the weather began to appear.

Steps to Reproduce:
1. /gamerule doDownfall false
2. Wait for weather.

See attached screenshot.