Found a new glitch that lets you hop on water under certain conditions. I've tentatively named it Phantom Log. Apparently when you touch the corner of a passing log's hitbox, you have an 11-frame window to hop onto a water tile adjacent to it. Though on frame 2318, Frogger seems to be able to stay on water for up to 40 frames with only one edge of a log near him. More testing is needed.
There are also water tiles like the first one I step on that are always safe to land on. Maybe the developers forgot to set them as hazardous.
Having hitboxes visible might make this easier to diagnose. They shouldn't be too hard to find with RAM Watch.
Uses BizHawk 2.6.3. Author's commentary is included as Subtitles. They appear at a Y-Position of 480 if your BizHawk window is big enough.