Rebalance failure during 4.1 -> 5.0.1 upgrade

Following the documentation for https://developer.couchbase.com/documentation/server/5.0/install/upgrade-individual-nodes.html for upgrading 4.1 -> 5.0.1 and my rebalances keep failing due to this error:

Rebalance exited with reason {unexpected_exit,
{'EXIT',<0.24631.1>,
{wait_seqno_persisted_failed,"data",280,
5181357,
[{'ns_1@kw1-couchbase01.admin.net',
{'EXIT',
{socket_closed,
{gen_server,call,
[{'janitor_agent-data',
'ns_1@kw1-couchbase01.admin.net'},
{if_rebalance,<0.24449.1>,
{wait_seqno_persisted,280,5181357}},
infinity]}}}}]}}}

   Rebalance exited with reason {unexpected_exit,
    {'EXIT',<0.6405.3>,
    {dcp_wait_for_data_move_failed,"data",799,
    'ns_1@kw1-couchbase05.admin.net',
    ['ns_1@kw1-couchbase01.admin.net'],
    {error,no_stats_for_this_vbucket}}}}

I’m able to restart the rebalance and continue but it’s hindering the upgrade process. The failures are occurring every 5 minutes.

I’ve started an upgrade from 4.1 -> 4.5.1 instead, and I’m not getting any rebalance failures.