There is an issue on our site where if a new user with no saved address tries to add a new address then the screen just refreshes and the address is not saved. If an existing user who already has an address tries to edit their address then it works fine.
There is an error message within the exception log which states:
Blockquote RR (3): User Error: Some transactions have not been committed or rolled back in /lib/Varien/Db/Adapter/Pdo/Mysql.php on line 4039
and there is a debug array:
( [entity_id] => 11295 [entity_type_id] => 1 [attribute_set_id] => 0 [website_id] => 1 [email] => firstname.lastname@example.org [group_id] => 1 [increment_id] => [store_id] => 1 [created_at] => 2019-10-07T10:33:26+01:00 [updated_at] => 2019-10-07 09:33:26 [is_active] => 1 [disable_auto_group_change] => 0 [created_in] => English [firstname] => fname [lastname] => sname [password_hash] => 35a2fbc591e3a006f7c8199e65c3e025:7laoLXnur6NAvZ9rHYRYBnClKkNWxbeW [middlename] => [password_created_at] => 1570440806
The only thing I can see that's missing from there that may be important is the increment key.
I have checked and all the relevant formkey fields seem to be in the form.