it probably isn't a bug or other fields would have the same issue. if the default is a comma decimal symbol and the other fields are responding correctly and you don't have a type assigned like text versus decimal number etc, i'm not sure what could be the issue.
have you tried 10,8 in the field? maybe if that works, then maybe there is a bug - then change 60,5 to 6,5 and see if the number is merged. if so, maybe values less than 10 cause the decimal to merge on the mac orr on systems using "comma" as the decimal symbol.