Hi Aslak,
Thanks a lot for your response. The issue is fixed now and this is how I fixed the same
In the code where I was generating the GATT_Notofication, I now have a code to check the return value. If the return value is either MSG_BUFFER_NOT_AVAIL or bleTimeout then I am retrying to send the notification again, with the assumption that in future the transacton may succeed. If the return value is bleNotConnected then I am just dropping the packet without trying to stress the LL layer.
With that change in place and with reducing the connection interval value to a lower value like 10, i am now successful in sending and receiving all the packets without any drops so far. I have collected more than 15 minutes of data multiple times and so far everything seems to be just perfect.
Thanks a lot for your help and hints.
Biswa