Thanks for your library, but my problem is solved. It's working fine now.
As I said, I just need to change a couple of lines in your AdaEncoder.cpp.
But of course, the changes I did are hardcoded specific to the PEC09 Bourns encoder I'm using.
If on another project, I use a different encoder, I may need to change the AdaEncoder.cpp again (back to your original code).
I'll try to submit some code to maybe implement either the LOW/LOW-Detent or the HIGH/HIGH-Detent condition so the library can execute what's appropriate for the encoder type.