For casual roundabout, I agree, and I fix it sometimes too.
Here we have an example of exception when it shouldn't be disjoint.

It's caused by junction topology – you can turn right directly BEFORE entering the roundabout, which would be wrongly entered by navigation software.

E.g., it could tell you to enter the roundabout and use first exit, but it would be incorrect.

In this specific junction, it can be controversial about some of them like from "
Pryzmaty" to "Wschodu Słońca" or even "Jutrzenki" to "Pryzmaty", but "Wschodu Sł
ońca" to "Jutrzenki" should be clear to you that it's possible to not enter the roundabout.

The other way to map it would be probably creating separated highway line to just turn before entering the roundabout, but there is no physical separators between the roundabout (like paved traffic island), so it would be incorrect to map it in that way :)

There was at least one user who write about it in "Discussion" section, but I believe it's just rare exception, that's why it doesn't have own paragraph.