[Bug] keyTimeFormat of tooltip not work

Description

const spec = {
  "type": "line",
  "data": {
    "values": [
      {
        "time": "1744859339559",
        "value": 8
      },
      {
        "time": "1744859349559",
        "value": 9
      },
      {
        "time": "1744859359559",
        "value": 11
      },
      {
        "time": "1744859369559",
        "value": 14
      },
      {
        "time": "1744859379559",
        "value": 16
      }
    ]
  },
  "xField": "time",
  "yField": "value",
  "axes": [
    {
      "orient": "bottom",
      "_alias_name": "xAxis",
      "label": {
        "formatMethod": function (label) { return new Date(Number(label)).toLocaleString(); }
      }
    }
  ],
  tooltip: {
    dimension: {
      content: [{
        keyTimeFormat: 'yyyy-MM-dd HH:mm:ss'
      }]
    }
  }
};

- OS:
- Browser:
- Framework:

Contributor guide

Tech stack

typescript

Domain

frontend

Issue type

bug

DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.

3

Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.

1-3 hours

Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.

blocked

ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.

clear

Prerequisites

VChart tooltip APITypeScript basicsTime formatting patterns

Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.

50

Research direction

Examine the source code handling the `keyTimeFormat` property in the dimension tooltip. Look for where the format string is applied to the time value in the tooltip rendering. Check if the property is correctly passed through the tooltip content configuration. Consider reviewing any existing tests for dimension tooltip to understand expected behavior. Debug with the provided reproduction spec to identify where the format is lost.