Nftables not working correctly with latest builds

Hi there!
I've got same problem as in this topic:

Same strange problem with "flush ruleset" not working from same config with rules to setup.
And there is more actually. I can flush ruleset manually but there is new problem for me.
I put a masquerading rule and it set without problem. But it just doesn't work. Packets being forwarded without any source alteration.
Firewall rules works at least partially.
I removed iptables modules from the system but problem is still here.
And I can add that I have a Debian 10 chroot on the system and nft binary from Debian give me same result. So I suppose the problem must be in kernel.
Initially I stumbled on this problem on 18.06.4 and later I upgraded to 19.07.0-rc2.
Upgrade does not change anything for me. Problem still persist with a new branch.