OptiFine is freezing fluid animations. How do I fix it?
Solution 1:
This is an issue that other people have had with OptiFine 1.17. It has been fixed in the newer preview.
The 1.17 version of OptiFine is still in preview, so bugs like this are expected. Just go back to the downloads page on optifine.net and download the latest preview, or if it has fully released by the time you read this, download the non-preview version.