Currently the Wikidata dispatchers use the redisLockManager defined in mw-config wmf-config/filebackend.php. This lock manager has the (default) lockTTL of 1 hour in CLI mode, which might be appropriate for some usages, but it's not for ours: We can't have the dispatchers stuck for so long in case something goes wrong.
I suggest to configure a new (redis based) lockmanger either specifically for this, or generally for "short lived tasks" with a lockTTL of maybe 5m.
(This may or may not be the reason behind yesterday's dispatch trouble, I can't tell… although given it lagged behind for such a long time already, it might not).
The lock manager could be defined as:
$wgLockManagers = [ 'name' => 'OUR-redisLockManager', 'lockTTL' => 150, // 5m 'class' => 'RedisLockManager', 'lockServers' => $wmfMasterServices['redis_lock'], 'srvsByBucket' => [ 0 => $redisLockServers ], 'redisConfig' => [ 'connectTimeout' => 2, 'readTimeout' => 2, 'password' => $wmgRedisPassword ] ];