You need to connect the database blocks outputs before the algorithms blocks.

To reproduce the bug: First connect the synchronization channels between two blocks of the algorithms until the analyzer, after them connect synchronization channel between the block of the database and the first block of the algorithm.

Problem: The system marks the synchronization channels between the algorithm as black color (unknown channels). Reported the error: "Invalid synchronized channel"

Solution: Delete the synchronization channels between the blocks and connect in order starting from the database block.