Corporate VPNs often restrict routing/forwarding.
Perhaps your VPN allows to access only specific subnets such as this one:
So, try to disable default gateway redirection in the VPN connection settings:
nmcli connection show
nmcli connection modify id VPN_CON ipv4.never-default yes ipv6.never-default yes
nmcli connection down id VPN_CON
nmcli connection up id VPN_CON