Open a Base database file with direct connection to PostgreSQL.
Go to Tools → SQL.
Execute
CREATE TABLE "public"."TestSerial" ("ID" SERIAL PRIMARY KEY, "Name" VARCHAR(50));
CREATE TABLE "public"."Test Serial" ("ID" SERIAL PRIMARY KEY, "Name" VARCHAR(50));
Two tables will be created. Only difference between this tables is the space in second table name.

Refresh tables (View → Refresh tables)
Open the tables for input data.
Write something in field "Name" and save value by moving cursor down to next row.
You will get "ID" = '1' in table "TestSerial". Next row will show "ID" = 2 and so on.
You will get always "ID" = '0' in table "Test Serial". The table name with space will stop refreshing of the field "ID". You have to reload the table to get the right values, which are inserted by PostgreSQL to "ID".

Note: You can't change content of a field, which shows "ID" = '0', because this value for "ID" doesn't exist in PostgreSQL table, but Base GUI will try to change content for a row with ID = '0'

This buggy behavior seems to be a very old bug. Have tested it under OpenSUSE 15.3 64bit rpm Linux with LO 7.4.3.2 and also LO 6.4.7.2.