unbound becomes stale after transport interface flap

hi

I experience pretty same behavior of unbound: often it becomes stale after
transport interface flap

In my VPN I have DNS server which serves local zones.

For clients I configure unbound to forward requests for those zones to
that DNS server, and when VPN interface flaps of re-keying occures,
unbound misbehaves and nothing valuable appears in log files

so, please advise, where to look at?

- ---[ unbound.conf quotation start ]-------------------------------------------
domain-insecure: "abc."
...

private-domain: "abc."
...

local-zone: "abc." transparent
...

include: /var/unbound/conf.d/*.conf
- ---[ unbound.conf quotation end ]-------------------------------------------

- ---[ conf.d/stub-zones.core.conf quotation start ]----------------------------
stub-zone:
        name: "abc."
        stub-addr: 1.2.3.4
        stub-prime: yes

stub-zone:
...
- ---[ conf.d/stub-zones.core.conf quotation end ]----------------------------

- --
Zeus V. Panchenko jid:zeus@im.ibs.dn.ua
IT Dpt., I.B.S. LLC GMT+2 (EET)