Will the Journey of Company Traffic to Mainland China Be Detected by the Great Firewall?

The mainland China entrance server, situated within the Great Firewall's (GFW) vicinity, routes traffic via a dedicated link to a Hong Kong server, which operates a reverse proxy using squid. The supplier has assured that this segment of the journey is not prone to detection by the GFW. However, the question remains: Will the company's mainland China entrance address be subject to detection? It is plausible that the company's mainland China entrance server will not be traversing the GFW, but are there other possible detection methods at play? The simplicity of squid's connect method in performing proxy operations raises concerns that it may be easy to identify the actual websites being accessed, thereby compromising the company's online security.