Progress tracker not reloadable in checkpoints written in Java

Can be replicated using the test on this PR: https://github.com/corda/corda/pull/4933
The test might need to be run a couple of times, as the node needs to be killed at just the right moment

The log of the test:

The log of the node:

Basically when the node is killed after the Issue subflow succeeded, the Payment subflow fails with that ProgressTracker error that prevents it from finishing.

More log:

Update:

The issue is that the ProgressTracker.Step class does not implement: equals/hashcode and thus deserialized Steps do not match the steps from the instantiated progress tracker.