New observations: IRST conflicts even after being removed:
How to reproduce:
1 Clean Windows install
2 Install mentioned IRST version
3 Try Bitlocker: uses software encryption
4 Uninstall IRST
5 Try Bitlocker: Wizard uses hardware encryption, but after system check reboot, Bitlocker dissapears from Windows. No lock sign on drive. It asks for a password on boot, but pressing ESC just boots the pc, meaning it's not encrypted. Doing 'manage-bde -status C:' in CMD gives:
ERROR: The volume C: could not be opened by BitLocker. This may be because
the volume does not exist, or because it is not a valid BitLocker volume.
The only way I have found to get everything back to normal is reinstalling Windows. You can't disable or properly enable it without reinstalling
When I just clean install Windows and then encrypt, without ever having IRST, it works as expected.