mobile client authorization problems

[Fidoshnik]

Greetings!
After updating the authorization server from 1.1 to 2.0, I discovered a number of features. I would be grateful if you could help clarify some points.

1. Made a switch but a new version. Correcting the configuration file config_db.php and config_ldap.php
   The server started up normally, but all users who used the Web client and the app client lost their session. They had to re-login. But users with a client on smartphones remained working and did not even notice anything. Is this the expected behavior?

2. After that, I tried to check the authorization from the mobile client. But then a bad surprise awaited me. I got an error on any device like in the screenshot
   

3. I began to understand and found the following error in php-fpm
   

I changed the following line and "it seems to work" but I'm not sure if this is the right approach. After that, 1 more time I got this error, but the rest of the inputs were successful. Can you tell me how to get rid of this error permanently?

The error is written to the log all the time, but everything seems to work. How to get rid of the error or is this normal behavior?

4. There is also another error in the httpd log
   

If these problems are local and conceived in this way, then ok. But I don’t like when extra errors are written to the log, which can complicate debugging

[Fidoshnik]

So, after some tests, I came to the conclusion that point 2 is solved as follows:

1. When you click the "login via Gitlab" button, the mmauth page opens in the browser where information is entered.
2. If you enter it incorrectly for the first time and get an error and immediately try again, this error will be generated.
3. The fact is that in the browser, each opening of mmauth creates a separate tab, because of this, an error occurs (perhaps the server is trying to read another open tab).
4. It is necessary to close ALL tabs with the mmauth service in the browser on the mobile device and try to log in again - everything should work out.