Because tekkengamewin64shipping.exe manages network connectivity for online matches, some overzealous antivirus software (especially Windows Defender at times) flags it as a "network threat." The executable is removed, and Steam complains that the "executable is missing."
The team began to investigate, running scans and analyzing the file's code. As they dug deeper, they discovered that "tekkengamewin64shipping.exe" was, in fact, a custom-built tool created by a former employee, Alex, who had left the company six months prior. tekkengamewin64shippingexe