For 6.5.2 and browser set to de_DE, the built-in number converter reacts different from previous versions and other locales.
It ignores the "percent" feature of decimal format and also the standard decimal separator is wrong.

Steps to reproduce:
Run the attached MVVM page with 6.0.x and 6.5.2-FL with de_DE and en_US. Check the displayed double value in the second line.

For me it displays:

6.0.2.1 2012090617 de_DE
314,16%

6.5.2-FL 2013031817 de_DE
3.14%

6.5.2-FL 2013031817 en_US
314.16%