Resolved.
Just in case other Pro 9 users come up against this.
The 50% Battery Limit function set in the UEFI does NOT work with Surface Dock 2, it only works with the included charger. A bit short-sighted considering if you're running 2x4K monitors or have other devices connected, then the Dock 2 will be powering the Pro 9 almost permanently. Thus not having the ability to limit battery charge other than the 80% limit (decided by Microsoft) is rather bizarre.
Just in case other Pro 9 users come up against this.
The 50% Battery Limit function set in the UEFI does NOT work with Surface Dock 2, it only works with the included charger. A bit short-sighted considering if you're running 2x4K monitors or have other devices connected, then the Dock 2 will be powering the Pro 9 almost permanently. Thus not having the ability to limit battery charge other than the 80% limit (decided by Microsoft) is rather bizarre.
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