Moved to the Fusion forum.
So,you have font issues on the Mac and font issues within the VM? Just to clarify.
You should upgrade Fusion to 10.x as that is the version supporting High Sierra.
But you may also want to clear the NVRAM or PRAM and perhaps reinstall Fusion.
Edward L. Haletky
vExpert 2009-2017, VMTN Community Moderator
Is your Ubuntu 17.10 guest running on Wayland session? If yes, would you please switch to xorg session and see if it helps?
Also, does the font display well if 3D acceleration has been disabled?
Last question, are you running VM with open-vm-tools or VMware Tools?
Same issue in Sierra 10.12.6, here are the details for me.
1. It only happens when my computer using it's AMD Radeon R9 GPU.
2. Only happens when 3D acceleration is on.
3. does not happen when login using xorg.
Before someone suggests I disable the discrete graphics, that's not an option when using a 34inch ultra-wide 3440x1400 res display.