In Pathfinder, the "Size Decrease Templates" don't appear to be altering ability scores (even though the sizes seem to be changing.) There's a table for the ability score changes by size here:
Note that the Young creature template seems to be working, so if a change in fixing the Size Decrease templates would affect the Young Creature template, then it will need to be adjusted as well.
Yeah, how annoying this was never realized. The system only works if you increase in size... This will not be back ported to 6.4.1 too much risk in breaking things.
Completed: At revision: 25371
All the size changing items will need to be tested extensively. This is not a candidate for Backport...
Also note to self, switching to GIT would have made this a bit easier... Fix could have been placed in a separate branch...
This seems to be working. Only snag I ran into was dropping some of the larger sizes (G, C) down makes their natural weapons wielded as if two-handed (at least it says so on the sheet.) The Young Creature template seems to be not working either (I threw it on an ogre and got -12 Str, +6 Dex, and -8 Con. Should I write these up as new issues?
If you want to open a JIRA for the items this "fix" broke, I would appreciate it. For the Young Creature, that is going to ignore size changes completely, since the numbers are not set to work within the confines of the Size Table.
I'm in process with my GIT guru getting branch 6.4.1 set up for a final 6.4 release before we move into future 6.6 changes that will not be backwards compatible with 6.4's engine.