Authentication sometimes fails

[Taraman17]

I have a problem, that sometimes (meanwhile close to 50%) the authentication fails. No answer is sent from the module.

Logging whats happening, I found that sometimes the 2 Authentication packets are sent by the server (or at least received by rcon-srcds) as 1:

writing packet
packet written.
received packet:
<Buffer 0a 00 00 00 99 09 00 00 00 00 00 00 00 00 0a 00 00 00 99 09 00 00 02 00 00 00 00 00>
decoded packet:
{
  size: 10,
  id: 2457,
  type: 0,
  body: '\u0000\u0000\n\u0000\u0000\u0000\u0019\t\u0000\u0000\u0002\u0000\u0000\u0000'
}

a correct set of packets looks like this:

writing packet
packet written.
received packet:
<Buffer 0a 00 00 00 99 09 00 00 00 00 00 00 00 00>
decoded packet:
{ size: 10, id: 2457, type: 0, body: '' }
received packet
<Buffer 0a 00 00 00 99 09 00 00 02 00 00 00 00 00>
decoded packet:
{ size: 10, id: 2457, type: 2, body: '' }
Auth response is success