A working example of the bug is at https://dojo.telerik.com/EPuqExOg with a simple workaround until the bug is fixed. Currently, the percentage textbox doesn't work when in the German language. The date textboxes localize ok.
Hello James,
This issue is not reproducible with the latest official version: https://dojo.telerik.com/EPuqExOg/7
Regards,
Ivan Danchev
Progress Telerik