Yeah that’s fixed it.
I tested this by cloning the original source, checking out the version tag for 0.10.4, reverting the commit (d68bcbd, the one @josch suggested) and then creating a patch with git format-patch, then grabbing the package source with apt-get source waybar and applying the patch with patch and building the package… If there’s a better way of doing this please let me know!
I’m wondering though if this patch would need reverting if the charge_now file gave the correct value instead of always being equal to charge_full?