Is it normal the wiki states April 2020? I have the feeling that what really concern most of posters in this thread with a lot of XP is what will happen in January/April 2021, no?
It is really not the same thing to say that you will be deducted 300XP in April 2020 (it would be "fair" compared with Plats having a qualification period ending in December 2019 who already got deducted) and to infer that the same will happen in April 2021.