Operators "+=" donīt work !!!

["Internet-Wifi Operador" <internet-wifi@hotmail.com>]

I have a s sqlcounter
Like Max-All-Session
until 2 or 3 weeks ago when I did use this with '+=' operator it work 
prefect because add some time to the user.
2 or 3 days ago it stop to work

Somebody any Idea?


Fabián

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