The bug

Snapshot 15w43b for 1.9 fixed MC-35790, an issue that made water hard to see through against glass due to it displaying the flowing texture. The fix made it display a flat, solid-colour texture instead. However, this also changed how glass looks from inside of the water - no texture is rendered against the glass at all. It'd be expected that the same flat water texture would be visible from inside the water, but this is not the case.

The inner top texture is correctly rendered against glass blocks (however it also renders some excess water textures incorrectly - see MC-175133). The inner bottom texture is not rendered in any circumstances at all, even though it should be - see MC-190053.

How to reproduce

1. Build a hollow stone cube with glass windows (example world provided)
2. View the windows from inside

Expected result

Translucent blue texture would be rendered on top of the glass.

Actual results

It is not.