When world has been generated, the textures of ALL water blocks (source and water) are the texture of blaze powder.

The texture of the water seems to be blaze powder. Behavior of the water has not changed. This may have been caused by the update of how blocks are rendered.

I made a short 1 minute video that fully shows the situation: https://www.youtube.com/watch?v=UDSWgf9zkEA

Thank you for taking your time in reading this.