My goal is to match specific files from specific sub directories. I have the following folder structure

`-- data
    |-- a
    |-- a.txt
    |-- b
    |-- b.txt
    |-- c
    |-- c.txt
    |-- d
    |-- d.txt
    |-- e
    |-- e.txt
    |-- org-1
    |   |-- a.org
    |   |-- b.org
    |   |-- org.txt
    |   |-- user-0
    |   |   |-- a.txt
    |   |   |-- b.txt

I am trying to list the files only inside the data directory. I am able to get the correct result using the following command in RHEL

find  ./testdir/ -iwholename "*/data/[!/].txt"
a.txt
b.txt
c.txt
d.txt
e.txt

If I run the same command in Ubuntu it is not working.

Can anyone please tell me why it is not working in Ubuntu ?