The decimal place is only considered up to the 5th decimal, such as 2.5 for example.
Therefore, if the Rating receives a value such as 2.1, 2.2, 2.3, 2.4, 2.5, it normally presents, as in the image below.
After the decimal 5, the decimal place is disregarded, rounding up to the next whole number.
So, if the Rating receives a value such as 2.6, 2.7, 2.8, 2.9, it presents incorrectly, as in the image below.
The problem is not in the filling of the stars, since Kendo makes it clear in its documentation that even the decimal 5 is considered as a half star, from that it would really be an entire star.
The problem is related to the label, which in this last example should have “2.6 / 5” instead of “3/5”.
In the link below to see a simulation.