Why isn't the city tax being collected on my ecommerce platform?

[TireSupplyNetwo]

Anyone else have issues with Shopify Tax? For example, order comes in from Grand Saline, TX, 75140. Why isn't Shopify collecting the 2% Grand Saline City Tax? The TX 6.25% is being collected, but for this example, the CITY TAX was not. 

Other times (and in other states where I collect tax), it's the COUNTY TAX that isn't collected. 

Anyone have any insight?