Steps to recreate:
Checkout branch release-enterprise-V3
Modify it to use to use the correct artifactory repository
In the root build.gradle, update ext.corda_release_version = '3.2'
From the root directory run gradlew :kotlin-source:deployNodes
Copy corda.jar and corda-webserver.jar from the O/S 4.0-RC01 artifacts into the kotlin-source/build/nodes/PartyB directory
Delete persistent.mv.db and persistence.trace.db from the kotlin-source/build/nodes/PartyB directory (there is no DB upgrade path from ENT 3.2 -> O/S 4)
In PartyB, self issue some cash by running: flow start CashIssueFlow amount: "10 GBP", issuerBankPartyRef: "1234" , notary: "O=Notary,L=London,C=GB"
In PartyB, make a payment to PartyA by running: flow start CashPaymentFlow amount: "10 GBP", recipient: PartyA, anonymous: false
And then hangs.
The logs for PartyA show a serialisation error:
(full log attached}