It seems in the latest Appstore macOS app the block-local feature, that often is pushed by the eduVPN server, doesn't work.
This feature should block access to local network resources when VPN has been turned on.

This feature should have been fixed in Tunnelkit:
partout-io/tunnelkit#96

In eduVPN App-log I read now:
2020-07-08 10:37:25.185 DEBUG OpenVPNSession.handleControlMessage():956 - Received PUSH_REPLY: "PUSH_REPLY,block-outside-dns,dhcp-option DNS 192.87.106.106,dhcp-option DNS 192.87.36.36,dhcp-option DNS 2001:610:1:800a:192:87:106:106,dhcp-option DNS 2001:610:3:200a:192:87:36:36,explicit-exit-notify 1,redirect-gateway def1 ipv6 block-local,tun-ipv6,route-gateway 145.90.228.129,topology subnet,ping 10,ping-restart 60,ifconfig-ipv6 2001:610:450:40::2:102d/112 2001:610:450:40::2:1,ifconfig 145.90.228.175 255.255.255.192,peer-id 17,cipher AES-256-GCM"
2020-07-08 10:37:25.188 INFO OpenVPNTunnelProvider.sessionDidStart():525 - Gateway: ["IPv4", "IPv6", "blockLocal"]