As kinerity stated: that is incorrect.
The problem/confusion arises from the Planned Release Table : 3.2.x OK
End of Maintenance: May 2019
End of Life: November 2019
and the keyword here is Planned, also note the green OK (compared to the red EOL for 3.0.x and 3.1.x)
Since phpBB3.3 hasn't been released yet, it is unthinkable that phpBB 3.2 would not be supported anymore, a version 3.2.9 is in the making and if necessary a version 3.2.10 will be released. Also support will not automatically stop the moment 3.3 is released (although I suspect that it won't take long before support wll be limited to upgrading).