Thread:Project:Support desk/time ParserFunction gives unexpected output

On the afternoon of July 31, 2014 I noticed the following behaviour: => 2014-07 => 2014-07  (<-same month?) => 2014-05

By Aug 1st, the same functions yield as expected: => 2014-08 => 2014-07  => 2014-06

Am I just using the function wrong? Tried it on my mediawiki.org talk page too with the same result. Are adjustments by month not doing what I think? Thanks!