I have zero clue why it needed a reinstall, but it fixed it.
I also noticed the same issue with non-RTP A1 sheets.Ī reinstall fixed the RTP water issue in terms of a river looking like it was flowing. I couldn't figure out why I've seen the effect elsewhere with the same RTP Outside tileset. I initially thought it was because there was a need for Parallax for *all* forms of tile animation, including for the RTP water (not just waterfalls or custom rivers). I had static water, using only the RTP tilesets.
Basically, the stock Outside RTP tiles one would use for the effect of a river flowing weren't animating.