help: custom syntax persisting despite being removed from config

[ricka-hunt]

Neovim version (nvim -v)

0.12

Neovim distribution

N/A

Description

I've set myself a few custom syntax functions using the built-in vim.cmd(syntax ARGS)
I've tried removing one of them vim.cmd('syntax match Emdash "—" conceal cchar=𖢊') from my config only to find that it's still active.
I've fiddled with everything, and discovered that disabling render-markdown results in expected behavior, and re-enabling it results in the "Emdash" matchgroup returning from the pale beyond.

What could be the reason for this, and how can I fix it?

Healthcheck output

==============================================================================
render-markdown:                                                            ✅

render-markdown.nvim [versions] ~
- ✅ OK neovim >= 0.11
- ✅ OK tree-sitter ABI: 15
- ✅ OK plugin: 8.12.0

render-markdown.nvim [configuration] ~
- ✅ OK valid

render-markdown.nvim [tree-sitter markdown] ~
- ✅ OK parser: installed
- ✅ OK ABI: 15
- ✅ OK highlights: ~/.local/share/nvim/site/queries/markdown/highlights.scm
- ✅ OK highlighter: enabled

render-markdown.nvim [tree-sitter markdown_inline] ~
- ✅ OK parser: installed
- ✅ OK ABI: 15
- ✅ OK highlights: ~/.local/share/nvim/site/queries/markdown_inline/highlights.scm

render-markdown.nvim [tree-sitter html] ~
- ✅ OK parser: installed
- ✅ OK ABI: 14

render-markdown.nvim [tree-sitter yaml] ~
- ✅ OK parser: installed
- ✅ OK ABI: 15

render-markdown.nvim [icons] ~
- ✅ OK using: nvim-web-devicons

render-markdown.nvim [conflicts] ~
- ✅ OK headlines: not installed
- ✅ OK markview: not installed
- ✅ OK obsidian: installed but should not conflict

Plugin configuration

vim.g.render_markdown_config = {
  render_modes = true,
  completions = { lsp = { enabled = true } },
  checkbox = {
    checked = { icon = "󰫈", scope_highlight = "RenderMarkdownCheckedItem" },
    unchecked = { icon = "󰋙", scope_highlight = nil },
    custom = {
      todo = { raw = "[-]", rendered = "󰥔", highlight = "RenderMarkdownTodo" },
      sixth = { raw = "[a]", rendered = "󰫃 ", highlight = "RenderMarkdownBullet" },
      third = { raw = "[b]", rendered = "󰫄 ", highlight = "RenderMarkdownBullet" },
      half = { raw = "[o]", rendered = "󰫅 ", highlight = "RenderMarkdownBullet" },
      twothirds = { raw = "[d]", rendered = "󰫆 ", highlight = "RenderMarkdownBullet" },
      fivesix = { raw = "[e]", rendered = "󰫇 ", highlight = "RenderMarkdownBullet" },
      ongoing = { raw = "[@]", rendered = "󰛡 ", highlight = "AltbgText", scope_highlight = "AltbgText" },
    },
  },
  link = {
    footnote = { superscript = false },
    wiki = { scope_highlight = "RenderMarkdownWikiLinkText" },
  },
  bullet = { icons = { "󰆧" }, right_pad = 0 },
  pipe_table = {
    preset = "round",
    alignment_indicator = "┈",
  },
  dash = {
    enabled = true,
    render_modes = false,
    icon = "─",
    width = "full",
    left_margin = 0,
  },
  latex = { enabled = false },
}