Foreign table & Connection reset by peer

Hi guys,

I would be grateful for some advice about foreign tables. I attached
simplified script describing the problem for better understanding.

What I am trying to do:

I am copying tables between two databases and for copying is used function
which are called from bash script.

What is problem:

I am creating foreign tables, selecting from them, dropping them and
everything works well. But always when I am working with them and the
session ends, message about connection resetting appears in log file of
remote database. It is showing "postgres(at)adam_db LOG: could not receive
data from client: Connection reset by peer". I am calling the command
often, so this message fill my log file quite a fast. I tried to find some
info about this message, without success.
Where can be problem?

Is there some different/correct way how to use foreign tables?
How can I closed connection properly?

For reproducing you can use attached script and after that execute next
command:
*psql -c 'SELECT * FROM ft_numbers'
"postgresql://localhost:5432/bety_db?user=postgres&password=postgres"*

I also tried to drop server after selection but it also logs the message.
Command which I executed:
*psql -c 'SELECT * FROM ft_numbers; DROP SERVER adam_server CASCADE;'
"postgresql://localhost:5432/bety_db?user=postgres&password=postgres"*
I tried to replicate problem in databases with different versions - all of
them ended with the message in log. Used versions:

- PostgreSQL 9.6.10 on x86_64-pc-linux-gnu (Ubuntu
9.6.10-1.pgdg16.04+1), compiled by gcc (Ubuntu 5.4.0-6ubuntu1~16.04.10)
5.4.0 20160609, 64-bit
- PostgreSQL 10.5 (Ubuntu 10.5-1.pgdg16.04+1) on x86_64-pc-linux-gnu,
compiled by gcc (Ubuntu 5.4.0-6ubuntu1~16.04.10) 5.4.0 20160609, 64-bit
- PostgreSQL 11.2 (Ubuntu 11.2-1.pgdg16.04+1) on x86_64-pc-linux-gnu,
compiled by gcc (Ubuntu 5.4.0-6ubuntu1~16.04.11) 5.4.0 20160609, 64-bit

Best regards,

Lukas