...It is because the default option with Update 5 is that upscaling mode is set to AMD. Reverting it back to normal disables the new sharpening effect.
For the record:

For the record:
- If you select AMD for upscaling, the sharpening effect is always active, even if you don't use any upscaling
- There appears to be no FPS difference between normal and AMD
- Setting it to normal appears to be the "old" way