This is *most probably* a reverser problem. But unlike you may think it is not a technical but an operational problem. You may know that EMB-145s are quite new for them, pilots transistioned from FK-50 and are not so used to the problem:
If you have a tail-engine aircraft, do not force the reversers in crosswind conditions! This problem is neighter new nor is it solved. Every now and then slips an MD-80 or alike into the grass. Luxembourg is also famous for its wind conditions.
I guess that LUX's OM says you should not use the reverser thrust, but reverse idle thrust is always allowed - otherwise you do something wrong with a jet: hitting the brake while applying idle thrust is not common among airliners...
Dani