IPIP tunnel broken until firmware upgrade

Hardware MikroTik hardware general
1

I was trying to use IPIP tunnels between repeaters and two different border routers, all with mikrotik.
The setup is this: every repeaters has two IPIP tunnels and using src-address with mangle rules, traffic is routed to tunnel or another.
As it is in testing, only a repeater works with this setup.

Without any visible cause, tunnel IPIP to a border router (which runs routeros 5.18) stopped forward traffic. IP addressing was correct, removing ad adding of interface didn’t resolved the issue. Sometimes rebooting both nodes solved the issue, but after one or two days, the problem reappeared.

The only workaround was to upgrade the firmware of the border router from 2.33 to 2.38. It is a RB 1200.

Has somebody got the same problem ?

2

It partially worked, but non definitively.
My new workaround is set the ip address on another tunnel, like EoIP, wait about 3-4 minutes and the /undo. But EoIP isn’t feasible, due to its overhead.