SplitString doesn't work with two delimiters

Summary

SplitString doesn't work with two delimiters.

System Information

• Operating system: Windows 8.1
• Processor architecture: x86-64
• Compiler version: 3.3.1-9600-g03ce2324 [2021/11/10] for x86_64
• Device: Computer

Example Project

program Project1;

{$mode objfpc}{$H+}

uses
  Types,
  StrUtils,
  SysUtils;

procedure RunTest;
var
  I: Integer;
  VStr: string;
  VArr: TStringDynArray;
begin
  VStr := '1-2; 3-4';
  VArr := SplitString(VStr, '-;');

  for I := 0 to Length(VArr) - 1 do begin
    Writeln(I, ': ', VArr[I]);
  end;
end;

begin
  RunTest;
  Readln;
end.

What is the current bug behavior?

Prints input string as is:

0: 1-2; 3-4

What is the expected (correct) behavior?

I expect 4 strings:

0: 1
1: 2
2: 3
3: 4