We're having the same issue on your test install as well.
Backtrace doesn't show much
#0 /home/nginx/domains/<domain>>/public/applications/core/sources/Setup/Upgrade.php(1254): IPS\_Db->query()
#1 /home/nginx/domains/<domain>>/public/applications/core/setup/upg_107640/upgrade.php(50): IPS\core\Setup\_Upgrade::runManualQueries()
#2 /home/nginx/domains/<domain>>/public/applications/core/sources/Setup/Upgrade.php(594): IPS\core\setup\upg_107640\_Upgrade->step1()
#3 /home/nginx/domains/<domain>>/public/applications/core/sources/Setup/Upgrade.php(326): IPS\core\Setup\_Upgrade->step1()
#4 /home/nginx/domains/<domain>>/public/applications/core/modules/setup/upgrade/upgrade.php(47): IPS\core\Setup\_Upgrade->process()
#5 /home/nginx/domains/<domain>>/public/system/Helpers/MultipleRedirect/MultipleRedirect.php(93): IPS\core\modules\setup\upgrade\_upgrade->IPS\core\modules\setup\upgrade\{closure}()
#6 /home/nginx/domains/<domain>>/public/applications/core/modules/setup/upgrade/upgrade.php(77): IPS\Helpers\_MultipleRedirect->__construct()
#7 /home/nginx/domains/<domain>>/public/system/Dispatcher/Controller.php(118): IPS\core\modules\setup\upgrade\_upgrade->manage()
#8 /home/nginx/domains/<domain>>/public/system/Dispatcher/Setup.php(220): IPS\Dispatcher\_Controller->execute()
#9 /home/nginx/domains/<domain>>/public/panel/upgrade/index.php(34): IPS\Dispatcher\_Setup->run()
#10 {main}
But since I'm awesome, I got you the queries it's running as well.
array (
0 =>
array (
'table' => 'core_polls',
'query' => 'UPDATE core_polls SET poll_item_class=\'IPS\\\\forums\\\\Topic\' WHERE pid in( SELECT poll_state FROM forums_topics WHERE poll_state IS NOT NULL)',
),
1 =>
array (
'table' => 'core_polls',
'query' => 'UPDATE core_polls SET poll_item_class=\'IPS\\\\blog\\\\Entry\' WHERE pid in( SELECT entry_poll_state FROM blog_entries WHERE entry_poll_state IS NOT NULL)',
),
)