Hi there - old post, but running into the exact same issue. Did you find a way to resolve it?
Topic summary
Main issue: On a nearly complete B2B Shopify site, pre-created customers’ default addresses (visible in Admin) do not auto-populate the shipping address at checkout. Only addresses previously entered by the customer appear, or the field is blank.
Observations: The default/address on file can be surfaced at the final payment step by choosing “change billing address,” where saved addresses are offered. The default address briefly appeared as an option earlier but behavior is inconsistent.
Attempts: Checked Shopify API and found only a “default” flag—no explicit shipping vs. billing designation. Tweaked checkout settings without effect.
Hypothesis/next steps: Possibly caused by earlier test data with Shopify remembering prior addresses; plan to try a fresh user in an incognito session to confirm.
Status: No confirmed fix shared. A later participant reports the same issue and asks if a resolution was found. The thread remains unresolved/ongoing.