My Jdownloads installation does not enforce download limits in all situations.
When testing with my test user, I reach the dowload limit and I'mn restricted from further downloads, as expected.
Still some users are able to download as many files as they like, over a short period of time.
To me it looks like the Limits system has some kind of flaw, but I don't know what's wrong.
Attached are screenshots of my testing results (as expected), the downloads log showing users downloading massive amount of files, exceeding the limits. (there are more examples) and a screenshot of the Limits settings I use.
I can give access to backend if anyone wants to have a closer look.