Fix tunnel data-ready notifications

The tunnel/direct data-ready traversal waves were not passing through.

Apparently, nobody has faced (in terms of data flow stalls) the bug yet in the currently being tested precedence rules topologies, which means the latter are not complex enough yet ;) Thus, the only consequence of this bug that developers might have been (unconsciously) observing in few special cases could be some degradation of the intra-event concurrency.

This MR fixes the bug.