By highlight breakups he means the highlights on the water - in case the white specks where light is reflected the most on your water surface and shines so bright it causes the bloom effect.
Since they’re only in groups of a couple pixel at most, the temporal anti aliasing smooths them out so your only solution to both have the highlights and the anti aliasing is to increase their size.
You can increase their size by either increasing the roughness slightly or using normals with softer edges or bigger shapes. Since your material is water the roughness option kinda drops out.