Open a database, which connects with the native driver to PostgreSQL.
Create a table in schema "public":
ID Int AutoValue
Name Varchar

You could see ID is set as Primary Kay and AutoValue is set to "Yes".
Save this table.
Don't close, look at the greyed out information: 
AutoValue is set to yes.

Close the dialog.
open the table for input data - no AutoValue could be found.

Close whole LO for new connection to PostgreSQL.
Reopen the database.
No AutoValue there.

Reopen the table for editing.
Look at ID - AutoVaule is set to "No".

You could create a AutoValue in Tools > SQL:
CREATE TABLE autor (
    id serial NOT NULL,
    name text NOT NULL,
    CONSTRAINT autor_pkey PRIMARY KEY (id)); 

With "serial" an AutoValue will be created ...

This bug appears in LO 6.4.4.2 on OpenSUSE 15.1 64bit rpm Linux. But it is also the same behavior, for example, in LO 6.1.5.2