Opticallimits

Firmware update for the RF 70-200mm f2.8 L IS USM, for the issue mentioned in above posts:

Firmware Version 1.0.6 incorporates the following fix:

・Fixed a phenomenon when performing AF shooting to capture a subject at close-range with the focus distance approximately set to the Tele-end (200mm), the image may become slightly front-focused.

This firmware update is for lenses equipped with firmware versions 1.0.5 or earlier. If the lens's firmware is already version 1.0.6, it is not necessary to update the firmware.

https://www.canon-europe.com/support/con...anguage=en

Ahahah, I love it when manufacturers use the wording "phenomenon" to avoid saying what it really is: a bug in their firmware code.
As if it were some strange thing that decided to manifest itself for some mysterious reason 

Please check here: https://en.wikipedia.org/wiki/Phenomenon (see paragraph "Science")
... there is nothing mysterious ;-)

Or just check a dictionary...

phenomenon |fɪˈnɒmɪnən| noun (pl. phenomena |-nə| )
1 a fact or situation that is observed to exist or happen, especially one whose cause or explanation is in question: glaciers are interesting natural phenomena.
2 Philosophy the object of a person's perception.
3 a remarkable person or thing. the band was a pop phenomenon just for their sales figures alone.
ORIGIN late 16th cent.: via late Latin from Greek phainomenon ‘thing appearing to view’, based on phainein ‘to show’.
usage: The word phenomenon comes from Greek, and its plural form is phenomena, as in these phenomena are not fully understood. It is a mistake to treat phenomena as if it were a singular form, as in this is a strange phenomena.

I can't argue regarding focus accuracy yet, but the AF is extremely fast ;-)