What I expected to happen: I would swim into my base (Through a water stream), past my pressure plates and iron door, and stand up.

What actually happened: I swam through a water stream, went through the door, and continued swimming.

Steps to reproduce:

1.Create swimmable body of water

2. Create a stream of water out of the previous body of water

3. Place a collisionless block in the stream

4. Swim through the stream

Bug in action.

Bug.mp4