Possibly not related specifically to the issue of updating the schema properly, but also upgrading from 2.1 and running 8201 update throws error because it attempts to update non existing tables (in my case, commerce_product__revision__field_duration).
Here's a patch for 2.2 while the whole issue is being looked at, which checks if the table is there before hand.
Based on #13 ✨ Send Drupal Core welcome email to new registrations during checkout Needs work , rerolled for v3.1.0.
albert.garcia → created an issue.
Updated patch #4 for version 3.0-rc10.
albert.garcia → created an issue.