Simplenews & Profile modules - error message

I am developing a site of the social network type, in which those interested in a given content type publications can receive messages for new posts of that content type through the simplenews module. At that old stage everything worked ok.

Yesterday, however, I added a Profile module so that registered users can add personal information so that their client account becomes their personal page.

After that I created a new profile (actually renamed the Label to the default profile "main" to be "Author profile") so that only users with the "Author" role have such an account and add some fields to that profile for CV, personal photo, links to account's social network pages or personal website, etc.

At the moment, only I can create new users on the site.

When I register a new user with the role "Author" in the registration form, the fields of the profile "Author profile" appear as expected and the registration completes successfully.

However, when I try to make any change to the client account and do not even make any changes, but only open the account for editing and save without change, the following error occurs. It does not matter whether I edit the fields defined by the profile or the standard fields of the user module - it appears even without any edit of some field:

Despite what is written in the message "The changes have been saved" no changes are saved and a white screen appears with this message. Access to other content on the site continues normally, it is simply not possible to edit user accounts with this role for which there is an profile.

It is not possible to edit a user account with an active role that has an activated profile.

When changing the role of a user account with one for which there is no active profile, for example from "Author" to "Authenticated" - then editing the user account is done without problems and error messages.

It is very strange that, as expected, the fields defined in the profile disappear in the user account edit form, but continue to appear when viewing the account, even though this account already has a role that should have no profile and corresponding profile's fields. Accordingly, it is not possible to edit these fields.

I found a temporary solution - when I want to edit the fields in the profile of a given account, I temporarily deactivate the simplenews module and when I finish editing profile's fields I activate it again.

However, if this issue is not resolved, I cannot authorize users to edit their accounts / profiles themselves.

Both modules, simplenews and profiles separately work perfectly, but somehow cannot work together at lest in this website.

I would be grateful for advice on how to solve the problem or idea to replace simplenews with another similar module that allows a notification subscription when there is a new post of a certain type of content, including a subscription from anonymous visitors.