Solved/Resolved : https://github.com/reactioncommerce/reaction/issues/4655
Even though Custom Rates are enabled they are not applied on checkout, however when looking at "Orders" in detail, the tax will be applied.
Port 1.17 Fix (https://github.com/reactioncommerce/reaction/pull/4664)
Reaction: 1.17 (https://github.com/reactioncommerce/reaction/pull/4761)
It does not seem like we can cherry-pick the fixes from #4664 as that relies on the 2.0.0 create order methods. We may be able to use the same concept, but will have to find the files that need to be fixed in the 1.17 release.
I believe this is only issue left blocking 1.17.0 I'll take a look at it tomorrow
Resolved by #4806