some supplier failed to calculate tax correctly while some supplier succeeded in calculation

Summary: Hi AP tax guru! Would appreciate your input. We are doing Italian AP tax and found some vendor can calculate tax correctly while some vendor failed to calculate tax. All other invoice data are the same except different vendor. I have checked the failed vendor and make sure that 1)"alllow tax applicability" and 2) "allow offset tax" are both enabled at supplier 1) profile and 2)address level. I am still seeing these vendor failed to calculate tax. Am I missing some setup from tax side like need to bedefined? third part profile