Mailchimp Subscribers sync not working on 4.2

Hi everybody,
we have activated Mailchimp sync for NOP subscribers, disabling "e-commerce data" option.
Without this selection, the sync does not works and contacts are not sent to Mailchimp.
We see that temporary plugin's table is correctly populated for each subscriber, but these data are not sent to mailchimp.

If we select "Pass E-Commerce data" all works fine, but in these case plugin sent all users to Mailchimp (not subsribers too) and we do not want this.

Is there a bug with the plugin or whatelse?

Thank you,
Marco

We too have issues with this plugin and have had some for quite some time now. I get this error when the sync task runs. We are running this on a multi store set up (3 stores).

MailChimp info.
Synchronization started at: 5/11/2020 6:14:29 PM
completed at: 5/11/2020 6:14:35 PM
finished operations: 12
errored operations: 10
total operations: 12
batch ID: b5ee750f00
batch status: finished
Synchronization errors:
http://developer.mailchimp.com/documentation/mailchimp/guides/error-glossary/ - Method Not Allowed - Operation delete-subscription-12150-list-1d57abbe69 - This list member cannot be removed.  Please contact support.
http://developer.mailchimp.com/documentation/mailchimp/guides/error-glossary/ - Method Not Allowed - Operation delete-subscription-12151-list-1d57abbe69 - This list member cannot be removed.  Please contact support.
http://developer.mailchimp.com/documentation/mailchimp/guides/error-glossary/ - Method Not Allowed - Operation delete-subscription-12152-list-1d57abbe69 - This list member cannot be removed.  Please contact support.
http://developer.mailchimp.com/documentation/mailchimp/guides/error-glossary/ - Method Not Allowed - Operation delete-subscription-12150-list-25342faada - This list member cannot be removed.  Please contact support.