Subject Invalid request BLR execting UNION of views
In a database, I execute the following code:

select *
from customer
select * from customer

The above does not make sense, it is a reduced query to show the error.

I get "Invalid token. invalid request BLR at offset 4275. BLR syntax error: expected record selection expression clause at offset 4276, encountered 24."

The first thought was a database corruption, but I have restored the database and passed the IBFirstAID application and no errors are detected. I use Firebird 2.5.

What else can I try?

Thank you