Limitations are fine. Undocumented limitations are a huge time-suck. Please aggregate a list of such issues somewhere so people have a realistic chance of being able to write working Jenkinsfile scripts without having to hunt around on the bug tracker for explanations of weird behaviour.
Writing up complete documentation is work like anything else, and everyone qualified to do it is overloaded. You can leave a vote on this issue like any other. Complaining about software you are using for free does not move anything forward.
Even better: where it is possible to do so simply (such as for inheritance) can we please have a nice readable error message instead of an incomprehensible one?