Incorrect 'no more matches'?

Hello!

I'm writing my first TextMate grammar and I can't figure out why (<->) rule does not math.
This is my pikchr.tmLanguage.json and my code sample is arrow <-> down 70% from last box.s.
To see that the rule doesn't match I run npm run inspect pikchr.tmLanguage.json example.pikchr

@@scanNext 5: | <-> down 70% from last box.s\n|
  scanning for (linePos: 5, anchorPosition: 5)
   - -1: \s*([\n;])
   - 13: ^\s*from)\s+
   - 23: (\bthen\b)?\s*(\bgo\b)?\s*\b(right|down|left|up)\b
   - 27: \b(\d*\.)?\d+(in|cm|px|pt|pc|mm|%)?(^|\s)
   - 28: ^[a-z_$@][\w$@]*
   - 29: \b(red|green|blue)\b
   - 30: %
   - 31: \b(close)\b
   - 32: (?=\s*")
   - 35: \b(diameter|ht|height|rad|radius|thickness|width|wid)(\s+)
   - 37: (<->)
   - 38: \b(same|cw|ccw|invis(ible)?|thick|thin|solid|chop|fit)\b
   - 4: \#(\s.+)?(\n|$)
   - 5: /\*
   - 6: (//).*$\n?
   - 8: ^\s*(box|circle|ellipse|oval|cylinder|file|line|arrow|spline|dot|arc|text|move)\b
   - 32: (?=\s*")
  no more matches.
  token: | <-> down 70% from last box.s\n|
      * source.pikchr

When I enable regexp debugging by adding | 8 to options (https://github.com/microsoft/vscode-textmate/blob/8b07a3c2be6fe4674f9ce6bba6d5c962a7f50df5/src/rule.ts#L884)

const result = this.scanner.findNextMatchSync(string, startPosition, options | 8);

the rule (<->) does match. Does anyone have any ideas what's going on? I'm using main branch and node v18.18.0.

Reproduce the report with npm run inspect pikchr.tmLanguage.json example.pikchr, then compare it with regexp debugging enabled. Start at src/rule.ts around findNextMatchSync and trace why rule 37 is reported as matching in debug output but ends with “no more matches.” Done means identifying and correcting or documenting that discrepancy, with a regression check if the repository’s existing tests cover the scanner.