Thanks Nick so I've gone ahead and installed rclone v1.54.0-beta.4971.e45716cac
Now situation is just a little bit better.
First, when I mount bitrix24 I can successfully copy directories with their files into the mount point using Linux commands.
But problems consist when using rclone commands. When I use for example 'rclone copy' I notice an odd behavior: now directories and files are all created on the remote, files 'ls -l' shows the correct size - but content in all files is just a mix of HTML and js. Still command exits with 0 no errors.... very odd.
Command I used:
rclone copy --verbose --transfers 30 --checkers 8 --contimeout 60s --timeout 300s --retries 3 --low-level-retries 10 --stats 1s /root/test bit:/testdir/
By the way Nick according to rclone changelog a similar problem with Bitrix24 was fixed by you in v1.46 already, so apparently it popped up again.