I found out that the problem is caused by shader I applied to all liberto emulators,
I guess Atari800 emulator doesn't like shaders.
Disabled it for this specific emu and it's working now!
Thank you mitu for answer.

@mahalingam it was fixed, so if you're getting the issue open a new topic with some info.

Please do not post a support request without first reading and following the advice in https://retropie.org.uk/forum/topic/3/read-this-first

The emulator itself supports both raw and .cas images.
I do not believe the scraper supports adding these images, so you would have to create a playlist manually.

The emulators.cfg can be modified to include the following commands:
-tape <filename> Attach cassette image (CAS format or raw file)
-boottape <filename> Attach cassette image and boot it
-tape-readonly Set the attached cassette image as read-only

I'd imagine it could work with this content in emulators.cfg:
atari800="echo %ROM: -\ % > /dev/null;/opt/retropie/emulators/atari800/bin/atari800 -config /opt/retropie/configs/atari800/atari800.cfg -boottape %ROM%"
default = "atari800"

Please note that i have not tried this myself.