Why order line Item Tax amount is different for same price , same quantity, and same tax rate ?

[Niravoza]

I have an issue with the tax price of the order line item.

I place an order with 4 items and the order tax setting is Instead Tax. 

The first 2 items are the same in price, quantity, and tax rate but with a different variant.

but the tax amount is different for the same tax type and tax rate in both line items, don't know how?

but for the rest of 2 line items in order with the same in price, quantity, and tax rate but with a different variant, the tax amount is the same for those 2 items

below I give the link of JSON data for this order 

https://pastebin.com/mFNE33zL

ScreenShot

1) Price = 23.24, Quantity = 1, Discount = 0, Tax Rate = 0.18, Tax price = 4.19
Price = 23.24, Quantity = 1, Discount = 0, Tax Rate = 0.18, Tax price = 4.19

2) Price = 23.24, Quantity = 1, Discount = 0, Tax Rate = 0.18, Tax price = 4.18

Price = 23.24, Quantity = 1, Discount = 0, Tax Rate = 0.18, Tax price = 4.18