Exception after Isotope Product Search

Hi

I have a problem after the update to Contao 3.3.6 with Isotope 2.1.9
The Search for "Produkte suchen" at http://weingut-meurer.de/nahe-wein-sekt.html throws two errors:

PHP Warning: Invalid argument supplied for foreach() in .. contao/system/modules/isotope/library/Isotope/Model/RequestCache.php on line 501
#0 /.. contao/system/modules/isotope/library/Isotope/Model/RequestCache.php(501): __error(2, 'Invalid argumen...', '/kunden/290286_...', 501, Array)
...

and

PHP Fatal error: Uncaught exception 'Exception' with message 'Query error: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '))
OR ...

Full log see attachment.

Any Ideas?

mysqli, 5-54STABLE-STANDARD and MySQL 5.6.19

THX!
Günter