Loading values at startup and with reload_all_from_gateway is exactly the same, there should be no difference. The same is for a CCU or Homegear. The binding also does not differentiate the channels by name, it treats all the same.
The values from channel zero, the one with the UNREACH flag, are always loaded, regardless of whether they are bound to an item or not.
What you can try is to switch the binding into TRACE mode, start OH or the binding, wait until everything has been initialize, then do a reload_all_from_gateway and send me the logfile. Also tell me the device addresses with the wrong UNREACH values. Maybe i find something in the log that I can narrow the problem.