The steps to reproduce are: 1) Install CITEXT extension 2) Create a table with a CITEXT column 3) Create a view (not materialised) over the table 4) Query the view filtering on the CITEXT column
No data gets returned when querying via the view, this works under Postgresql 10 but not 11.
There is no step here where you populate the table.
Add one, I can't reproduce this (on Ubuntu 16.04, so maybe that is important).