One hundred percent intentional. It could be changed, but as it stands right now the chains for the execute are their own targeted projectile that on contact with the target suppress them and begin the execute. If intercepted by Braum, they will suppress him instead.
Strictly speaking;
If the target is below 25% of their maximum health, Fear Beyond Death can be re-activated, and automatically does so after 3 seconds if the target is within the threshold.
SECOND CAST: Urgot begins channeling as he launches chains at the target, Suppression icon suppressing them on impact and reeling them in over X seconds, during which they are untargetable by other effects.
The channel can only be interrupted by Urgot's death. If the channel is successful, the target is executed and surrounding enemies are Fear icon terrified for 1.5 seconds.
The target of the first shot must be below 25% health for the chains to be able to fire, but after they connect, short of invulnerability, suppression removal, or killing Urgot, they execute the suppressed target at any health. Again, the 25% threshold is to fire them.