Suppose that Bob committed on Jan 1 an offence for which the statutory limitation period was 6 months, and then on Aug 1 of the same year, a law came into effect changing the limitation period (but not the potential sentence) of the offence to 1 year, and then he was charged on Sep 1 for the offence committed on Jan 1.
In any jurisdiction, is this a post-facto legislation of offence? I mean, it basically turned something that for the whole month of July Bob shouldn't have ever again been able to be punished for into something that he could again for the next five months continue to get charged with. But that seems not to be entirely the same thing as criminalising post-facto conduct which was at the time of its commission not illegal.
In your jurisdiction of knowledge, are there bars to such post-facto legislation extending the limitation periods for proceedings for past acts for which the deadline may have already passed?