Describe the bug

The following error message is printed to STDERR anytime I press the TAB key:

_zsh_autosuggest_highlight_apply:3: bad math expression: operator expected at `POSTDISPLA...'

To Reproduce

Steps to reproduce the behavior:

1. Open my zsh shell.
2. Press TAB
3. Watch error message print to console.

Expected behavior

No error message.

Desktop

• OS + distribution: Debian GNU/Linux 11 (bullseye)
• Zsh version: zsh 5.8 (x86_64-debian-linux-gnu)
• Plugin version: v0.7.0 / a411ef3

Additional Context

This just started happening yesterday seemingly at random (I did not update zsh, this plugin, or oh-my-zsh).