What I see is that you have echo enabled which puts extra load on serial connection that is not necessary.
Also the log is incomplete. You need the log written to work directory (if enabled) to see full communication. All I see here is
Error:Tu:
which I have never seen before and that somewhere a resend was triggered, but it is not visible where or why.
We haven't change the communication handling. Could it be that the receive buffer length is larger then 127 set?
