How to prevent automatic insertion of CLKCTRL

Hi,

I'm doing several builds of a design with different seeds in order to close timing.

In about half of the builds Quartus inserts CLKCTRL into paths with high fanout (shown in the attached screenshot).

Well, those paths result in -2.2ns violation (the clock is 266MHz).

In builds where Quartus doesn't insert CLKCTRL, critical paths are around -250ps.

Before I start playing with max_fanout, I'd like to prevent the tools inserting CLKCTRL because it doesn't do any good.

I did a quick overview of available QSF options, and found nothing that controls this.

The closest is AUTO_CLOCK_ENABLE_RECOGNITION, but I'm not sure.

Another question: why would a different placement SEED trigger this in some of the builds.

Thanks,

Evgeni