2d label and 3d label can not use same font on android ，
it will cause the font do not working after the 2d label and 3d label appear in the same time on android.
but in the windows editor it is ok
unity version :2018.4.23f1
tmp version: 1.5.1
Almost correct.
You can use the same font asset but not the same material preset. This is because the MeshRenderer used by the component and the CanvasRenderer used by the component have different ZTest as such they end up fighting over the ZTest which results in one or the other text object disappearing.
The solution is to use a different set of material presets for the object and the text objects.
But again, you can use the same font asset. Just be mindful that the font asset has a default material which is why you thought that you cannot use the same font asset.
P.S. There is a timing element to this where this behavior occurs more often on slower devices. Not sure why however.