The EU court sets binding precedents across the Union, but the law is still enforced at a national level and discrepancies can arise and take time to be cleared

The EU court sets binding precedents across the Union, but the law is still enforced at a national level and discrepancies can arise and take time to be cleared up. There's also the fact that Union law is not perfectly uniform in any case, there are national differences where they go beyond the minimum requirements of Union law.