Hi !
the Cisco OSPF has a higher lsa-lifetime ( as far as I remeber up to 18 hours) than JUNOS ( on JUNOS it is one hour )
OSPF advertises and updates prefix information using LSA messages, which are ... between 30 and 45 minutes, given the default 3,600-second LSA lifetime.
So without seeing more from the OSPF state try changing ane equalizing the lsa-life-time parameter on the CISCO router to 3600 sec
info about the lsa-lifetime you can find in any lsa-update ( show ospf database extensive on Junos)
hope that helps
alexander
