Chinese trackpad handwriting input not working after High Sierra upgrade?

I have a late 2015 iMac and I've just upgraded it to High Sierra. The Chinese trackpad handwriting was working fine when it was under Sierra. Now the handwriting trackpad shows up on the screen when the handwriting mode is triggered but when you try to write on the trackpad, it is not responsive; nothing appears, no even a dot or stroke to indicate that the computer is sensing my input. Does anyone have the same issue? Is Apple actively trying to resolve the bug?