The Tax Code 511 - Regular HST Sales is determined in a Sales Document for the Tax Country Canada. You expected that the Tax Code 501 - Regular GST Sales is determined.
SAP Business ByDesign
The Account is located in ON - Ontario. Hence, in the Sales Document the Tax Country Canada and Tax Region ON - Ontario is determined.
When you check the Tax Trace in your system you can see that the Tax Trace parses as false for GST the question because of the region ON – Ontario.
The region ON - Ontario is applicable for HST but not for GST as per the decision tree parameters.
Only a very limited number of products such as child clothing are applicable with 5% GST. Since, a majority of products/services are applicable for HST, the tax decision tree will determine the Tax Code 511 - Regular HST Sales.
This is the expected system behavior.
You can manually change the Tax Code to 501 - Regular GST Sale should the product be applicable for GST.
2427419 - How to use Activate Tax Trace
511; 501; Tac Code; Tax Determination; Canada; Ontario; GST; HST , KBA , SRD-FIN-GLO-TAX , GLO - Tax Declaration , AP-TTE-GLO , Cross-Country Extensions , Problem