[2020] L23A1 Underperforming contrary to Challanger Devblog post regarding L23A1 Penetration changes

This is not a bug.

The method of penetration calculation was changed in 2019 to a new system: https://warthunder.com/en/news/6010-development-improved-calculation-of-armour-penetration-in-the-game-en

What you are reporting is not using the new method and does not contain any of the information required that shows there is any issue.