[Pgpool-general] EXPLAIN statement fails on 'kind mismatch'

[asaf at lingnu.com]

hello

after 2 weeks pgpool-II (2.25) was working good,
I now have:
'kind mismatch among backends. Possible last query was: "EXPLAIN SELECT *
FROM ycore.transfer_record WHERE
transfer_record_id>400" kind details are: 0[D] 1[C]'

just when we wanted to move to production.

all other things still work, also 'EXPLAIN' on other tables,
(also same query on this table worked until now)
I have full logs of pgpool + 2 postgres backends
how can I find out whats wrong ?