@george1421 @Tom-Elliott
Luckily I could schedule a meeting with my System-Admin today, and he tried turning off the serving of the WDS boot file - seems in the configuration of option 66 and 67 of our companies DHCP server was an old Windows Server that served a meaningless WDS file, we changed it to my FOG Server and the issue is now solved.
I am very thankful for your first-class support and I apologize for the inconvenience! You guys are my heroes!