Local difficulty displayed (using F3) as being 2.25 everywhere in the world (on normal mode), but the wiki states it should change depending on the chunk. F3 says that it's Day 162.

After sleeping in a bed, local difficulty dropped to 2.13 immediately, and did not change, even when revisiting areas that previously displayed the local difficulty as being 2.25. Now Day 163.

Tried relogging to see if that reset the local difficulty to 2.25, or any other value, but that didn't seem to change anything.

Went mining, waited until Day 164 in a different chunk. When Day 164 started, local difficulty dropped to 2.00.

Probably only an error in the display, but I can't be certain.