Not surprised. Can happen with some host network settings.
"Repeater" is using the wifi as client/station in the hotel. However nothing is said about the "Network Mode".
If "Network Mode " is "Extender" then your ethernet coupled device will request its own IP address with its own MAC address in the DHCP payload but with the MAC address of the Beryl in the 'Discover' DHCP packet header. This might drop the DHCP lease for the Beryl, depending on the DHCP server and portal settings. (What will make the MultiWAN check to fail, what will stop that connection). Can happen with just standard network settings, no specific action against access sharing.
If "Network Mode" is in "Router" , then the host network actively fighting access sharing might see requests with different TTL values. Some networks don't want you to share your connection, and will shut this connection down.