If you read the first source [0] in the article, you will find the following refutation in the first page:
<<Consider the possibility that quarterly company earn-
ings announcements in the United States (outside reg-
ular trading hours) are responsible for the top row of
Figure 1 [15]. You can falsify this attempted explanation
by removing the returns around earnings announcements
and noting that this does not meaningfully change the
plots (as in Section 4.1 of Ref. [5]).>>
[0] https://arxiv.org/abs/2010.01727
