LENGTH('Chinese character') returns 2

Oracle Product : Oracle Database Standard 19.3.0.0.0

Plateform : Windows 2019 x64

Database character set : AL32UTF8

According to my understanding, The function LENGTH always returns the number of characters in a string.

However, when i execute it against a Chinese character,

select length('𡘙') from dual;

it returns 2.

The result is also the same when it is selected from a table:

select length(column_name) from my_table;

Is there anything going wrong ?

Thank you for your help.