Issue autoresponder creates heavy load

[Linulex]

Hello,

We upgraded about 15 server to plesk 17.8.11 this weekend and we now see on all that the autoresponder creates a very heavy load. The overall server load jumps from 3 to 14 (or more).

31001     popuser     99.9 %     /usr/local/psa/handlers/hooks/autoresponder responder opawai@ ...
9249     popuser     99.8 %     /usr/local/psa/handlers/hooks/autoresponder responder opawai@ ...
31201     popuser     99.8 %     /usr/local/psa/handlers/hooks/autoresponder responder opawai@ ...
19727     popuser     99.0 %     /usr/local/psa/handlers/hooks/autoresponder responder opawai@ ...

we use qmail and courier on centos 6.

"Send an automatic response to a unique email address no more than (times a day) *" in plesk is set to 1

has anyone seen this and knows a fix?

regards
Jan