The current table definition in the master of the table LEK_term_collection_taskassoc is:

CREATE TABLE `LEK_term_collection_taskassoc` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`collectionId` int(11) DEFAULT NULL,
`taskGuid` varchar(38) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=73 DEFAULT CHARSET=utf8 |

Here are missing foreign keys to the task and collection table.

A cleanup SQL must be also provided which deletes non existent entries anymore. This must be run before the foreign keys can be added.