You have me on this one. I would say it could be that fast boot/ fast startup is running, but then why would you see the boot sequence on the other display. You can try the steps below to see if it helps.
To Turn On or Off Fast Startup in System Settings...
1. Go to 'Control Panel' and click on the "Power Options icon".
2. Click "Choose what the power buttons do" on the left side.
3. Click "Change settings that are currently unavailable".
4. If prompted by UAC (User Account Control), click "Yes".
5. Do step 6 or step 7 below for what you would like to do.
6. To Turn On Fast Startup.
6a. Under "Shutdown settings", check the "Turn on fast startup box", click "Save changes", and go to step 8 below.
7. To Turn Off Fast Startup.
7a. Under "Shutdown settings", uncheck the "Turn on fast startup box", click "Save changes", and go to step 8 below.
8. You can now close the 'System Settings' window.
Note: If the "Turn on fast startup" setting is not listed, then you will need to close the "System Settings" window, enable "hibernate", and then start over at step 1 again.