Unbound DNS stops working several times a day

[bongo]

my OPNsense was working without any issues for month...until a few days ago.
when recognizing that i have no more internet access, i restarted OPNsense.
since then, Unbound DNS stops working regularly (turns red on the dashboard) and i need to manually restart it. this happens several times a day. never had this issue before.
what might go wrong?
my actual version is:
OPNsense 20.7.7_1-amd64
FreeBSD 12.1-RELEASE-p11-HBSD
OpenSSL 1.1.1i 8 Dec 2020

[bongo]

in the mean time, unbound stops every few minutes ;-(
how can i solve this?

[chemlud]

Had unbound stopping on 21.7.3_3amd64 with LibreSSL yesterday night (most likely, was down in the morning) together with suricata. Nothing in the logs, neither suricata nor unbound or general log. Only thing I see is spikes of high RAM and CPU usage (without traffic increasing from LAN) at random times.

Very annoying and no idea where to look.