I am from the same team , Adding a few more points
a) Connection Pooling is enabled
b) We have followed the standard EBS-ADF integration pdf by Sarah Woodhull
c) EBS - ADF session is established successfully
d) When we launch the adf page from inside EBS responsibilty , "Connection has already been closed" , Exception is being thrown , After this , No DB operation occurs.
e) When session management is disabled ,Everything works fine
f) We are using appsDataSource