Digital signature verification failed on TAB S6 lite

Not sure this is in correct project, please, move it to correct one (newbie).

Steps to reproduce:

1. download the dev build for Samsung Galaxy tab s6 lite
2. verify the sha256sum is correct
3. reboot to recovery
4. select update from adb sideload
5. use adb sideload

Expected result: Installation will flash the device

Actual results: after 47% the flashing process stops with error about incorrect signature

Note: I tried to use the same file also using microSD card, same result.