The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/12/collation.html
Description:
If exists statistic with nondeteministic collation inherited from column
collation then using pattern matching with collation will give an error.
There is no information about it. ((
I have seen this thread
https://www.postgresql.org/message-id/flat/CAAFmbbOvfi%3DwMM%3D3qRsPunBSLb8BFREno2oOzSBS%3DmzfLPKABw%40mail.gmail.com
But I can't apply this patch for some reasons.
If I knew about the problem I would not use nondeterministic collations and
choose another way.