clients timeout on net_read_timeout, server thread is in sleep state

We have a situation where we the clients timeout, during the timeout the connection on the server is in the sleep state.

It looks as the server replied to maxscale, but maxscale is not forwarding the reply to the client.

After some debugging we noticed the following:

• the server never replies to the sql command (traced via pcap)
• created a new db with a new table that only has the 2 affected columns, and even with this we can reproduce it
• the issue seems dependent on the query length
• 2800 = pass
• 2892 = fail
• 8187 = fail
• 4340 = fail