Error in log since migrated to V4.4

Strange I cannot reproduce.
In fact, there should be some unexpected "echo" (possibly some remaining debug tracing), but I cannot fond where.
As this error should appear dureing disconnection, could you figure out on which screen you are when you get this log and how you disconnect ?

Didn't you change some code and introduce some "echo" for debugging purpose ?

Hi,

It is strange to get this last error only once a day... (unless you use the "remember me function")
It confirms that setting header comes too late...

As I don't reproduce, I'm almost sure it come from one of your changes.
It is very difficult to find such issues because it can be due just to some space or line break before a <?php tag.
This sends some data to the buffer, and it is then impossible to modify headers.

It is for instance possible that you introduced some caracters before the <?php tag in the parameters.php file.
As you get this issue on connection and on disconnection whatever the actual page, I would suspect some change in a php file very frequently userd (parameters.php, projeqtor.ph, html.php,...)

I woukd recommend :
1) try with community version without any change to confirm this does not occur with community version
2) re-apply you changes
3) identify all changed code and seach for extra data out of <?php ... ?>