Hi there,
We started to investigate this on Avalara tax provider but the issue seems to be on the platform side and not related to any specific provider(s).
I tested using 2 flat rate tax providers to mimic the duplicate lines, as you can see in screencast when order is loaded the "duplicated" line is removed causing the subtotals to be off and sometimes leads into the checkout error The price of the order does Not validate with the sum of the orderlines - https://www.screencast.com/t/MxIHiNJJ
US can have multiple taxes with same description and sometimes amount, so this would be a valid scenario. I noticed that method CanBeMerged from OrderLineService takes some orderline types into consideration as GiftCards but does not check for Tax lines, treating them as regular lines. Would a simple fix be prevent tax lines to be merged?
DW version 9.15.1
BR, Mario
