Latency on an Artnet to DMX converter! - Enttec Ethergate MK3

Hi
I have the following problem with an Enttec ethergate MK3. Its a 2port Artnet to DMX
I connect it on my Full Boar4 and this is what happens. On DMX univ 1 thru 3 works fine. On DMX univ 4 there is a small latency ( about 0,5 of a sec). But at DMX Univ 5 and up the latency is TOO much - about 1 minute or so.
I checked the unit with an Artnet Software - QLC+ - . The unit seems to work ok with that. I also checked the console with an Artnet reader software - The Artnetominator- And the console also works fine!!!

I wonder, is there any know issues with the compatibility off my console and this converter?
I would appreciate if you could help me on that.

ps. I get the same result if I connect them with a ethernet switcher - router or direct. Also I tried Static IP and DHCP enabled. Same result again.
thanks for your time