Upgrade 3.0.2.0 -> 3.2.1-1 keywords being lost in upgrade

[This is a continuation of a thread at Upgrade 3.0.2.0 -> 3.2.1-1 / Duplicate entry 'XXXX' for key 'controlled_vocabs.controlled_vocab_symbolic' continued in a new thread as per the request of @asmecher ]

We have applied the patches for issue 6213 appear to have fixed most of the issues. In particular the migration now progresses without complaining and keywords can be assigned and saved.

However, keywords which had been assigned prior to the upgrade appear to have been lost. I’m not sure how much of a priority this is, since the keywords don’t appear to be displayed anywhere obvious. There is a possibly relavent error in the logs (it’s the only error we’re seeing in the logs):

[Mon Sep 14 14:48:01.935066 2020] [php7:warn] [pid 26405] [client 10.30.40.114:53680] PHP Warning: in_array() expects parameter 2 to be array, null given in /var/www/ojs/lib/pkp/pages/workflow/PKPWorkflowHandler.inc.php on line 373, referer: https://{{hostname}}/test/manageIssues

cheers
stuart yeates