Usually I simply restart such “hanged” router, and it helps for a 1-2 weeks…
As I wrote before, you can simply will not meet with this issue if your router not working with a lot of traffic and don’t using a snmp. At this moment I’m copying a lot of data between datacenters - on both ends I have installed a VyOS 1.2.7 LTS. On one router I don’t have snmp (and bgp with vrrp) enabled on the other end I’m monitoring a router with the Zabbix 5.0 via snmp also it has a ebgp session and vrrp enabled.
SNMP enabled router has fall two times per 10 days while copying a 6.5 Tb file via rsync, the average speed is ~ 100 Mbit/sec