i too have this condition while upgrading from 8.1.9 to 9.0.3-h3. the release notes and upgrade guide state i can upgrade directly to 9.0.3-h3 without the intermediate 9.0 step. however, this post led me to downgrade to 9.0 from 9.0.3-h3 and re-attempt a non-impactful upgrade. this did not fix my situation but i was able to continue my upgrade path, just with impact to user traffic. upgrade to 9.0 was impactful, but after both devices upgraded, HA2 came online and synchronization was successful. upgrade to 9.0.3-h3 from 9.0 was hitless and uneventful. also, i needed to upgrade my logging server to 9.x before logs would start showing up in panorama for this set of firewalls.
... View more