Hi Jie, Thanks for the response!
I checked the header size and found its not the issue..
No errors in the logs either .
I tested different users and every user token is cutting at 880 bytes and assumed this is because of the too many values.
Anyway, I found that its a limitation probably on the log local0 command. I log the token before sending it to backend servers, The logged token shows 880 bytes of base64encode token but the backend server logs show full token which is good.
In the conclusion, the whole token is being sent to backend but not logging the full token.