CPE Mode renders many sites unreachable

I have a RB951G-2HnD running RouterOS version 6.38.3 in CPE router mode connected to my universities WiFi and providing Ethernet to a few devices. For the most part they all have internet access however there’s a few websites I’ve noticed that simply don’t work, github.com and bash.org are two of them, when I ping them I get Host Unreachable errors, same problem from the router and from devices connected to it. These sites are reachable if I connect a device directly to my universities WiFi with no problems whatsoever. I’ve tried factory resetting the router numerous times and the problem has existed through at least the last 4 or 5 versions of RouterOS.

I’m currently bypassing the issue by connecting to a VPN whenever I need to access those sites, but I’d rather not have to. Any suggestions on what could be wrong and how to fix it?

What do you define as CPE mode?

To provide wifi-to-ethernet bridge, you should be running the WiFi interface as “station-pseudobridge”.