The EPO has developed a robust system called the "COMVIK" approach that provides a significant degree of certainty regarding what will be considered patentable. However, a point of contention lies in the incorporation of previous patent law, which deems what some would consider highly technical areas like natural language processing (including automated translation and chatbots) and financial tech (e.g., blockchain) as non-patentable.
It should also be noted that the EPO has recently been critical of sufficiency of disclosure of AI-related inventions, particularly those involving neural networks. Especially the availability of training data (or rather lack thereof) has been criticized (see e.g. decisions T161/18 and T1191/19).