Was LotR Return of the King shortened from the extended version to the standard version? [Canada]

Watching on Canadian netflix. I started it this week and was watching it bit by bit. When I started it again today, I noticed it started in a scene I didn't leave it at, so I went back to approximately where I was. In that rewatch, I noticed there were certain parts of scenes that were cut. Then I looked at the length of the movie and it went down from ~4h to ~3h.

Why was the longer version replaced with the shorter version?