Customizing PHP settings of locked Plesk subscription resets “open_basedir” parameter for subdomains

Symptoms

1. 
open_basedir
PHP parameter set as
null in Subscriptions > example.com > subdomain.example.com > PHP Settings .
2. Example.com subscription is locked.
3. Changing
memory_limit
PHP parameter in Subscriptions > example.com > Customize > PHP Settings causes the resetting of the
open_basedir
PHP parameter for subdomain.example.com to the default:

   PLESK_INFO: {WEBSPACEROOT}{/}{:}{TMP}{/}.

Cause

Plesk bug with ID #PPPM-7585 which is planned to be fixed in future Plesk updates.

Resolution

As a workaround:

1.  Log in to Plesk
2. Set the needed memory_limit
value in Domains > example.com > PHP Settings.
3. Set the needed memory_limit
value in Domains > subdomain.example.com > PHP Settings.