Generally speaking, no, if the server has received the request then it's unlikely to be a client bug, although certainly there could be a problem somewhere along the network route from the client to the server.
However, are you sure that the server really got the request? The timer name can be misleading; it really reflects the time at which the client finished writing the request to the network, but that doesn't mean that the server actually received it.
If you look at the Inspectors, what is the text in the TextView response inspector for the failing request?
Do you have a NetMon or Wireshark log of the failing traffic?
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