Hi @akocienia ,
So what happens here is that the detected tokens are actually ["50", "%"], and a pattern that describes one token with a regex wouldn't match. I'd recommend that you write a pattern that covers both.
It might also be useful to implement your own matching logic using regex over the whole text (Create new entities from regex - #3 by ines) . Just ensure that you won't have any overlapping spans 
The advantage of the latter approach is that you have total control of the implementation logic, and write some heuristics where, for example, you only take the longest span if there are any overlaps.