Jump + walk glitch

What I expected to happen was...:
When I stopped pressing the space/W key, I would stop jumping/walking

What actually happened was...:
I kept walking. I know this wasn't my keyboard because when I went into chat I could type normally

Steps to Reproduce:
1. Fall from a 2-block-high fall (no idea if this makes a difference), then press jump/forward.
2. You should keep on jumping/walking after you have stopped pressing
3. Note: It doesn't always happen, but recently it has started happening, and it is very annoying