Nerd Fonts do not render properly in ish

So far, every mono font with the nerd font patch has not worked properly and it is the same problem with every one of them - the cursor is several spaces ahead of where it should be compared to where the characters actually appear.
This may not seem like a huge problem, until you start to edit a document or even a command on the command line. The cursor is on a completely different character than the one it is modifying.

Fonts I have tried so far:
Fira Code NF
UbuntuMonoSpaced NF
SauceCodePro NF (Source Code Pro with NF patch)
Meslo NF (Menlo with NF Patch)

The report names no files, tests, or entry points; first reproduce the cursor-position problem in ish with one of the listed Nerd Fonts while editing a command or document. Done means the cursor aligns with the rendered character positions for the affected fonts.

Written by the indexing model from the issue text.