Bootcamp: My Mac Only Boots into macOS No Matter What Partition I Choose I have a 2017 Macbook Pro 15 inch running 10.13.5 and a bootcamp partition of Windows 10. I cannot boot into windows unless I select the windows partition from system preferences and restart from there.

If I try and hold down the option key on restart, Startup Manager opens but no matter which partition I click, it boots into macOS. It will not let me boot into windows this way.

Is there any way to fix Startup Manager/boot into windows?

Edit: Video on what is happening
AFAIK High Sierra already "introduced" APFS. The Bootcamp partition is formatted NTFS, I thought. If you set the startup disk to macOS in Settings (while in macOS), then, when you startup holding the Alt key, the boot window should let you choose between the two partitions. I cannot check now since I am a long way from base.
I am not sure when Startup disk is set to the Bootcamp partition, everything will work correctly as expected.