Bug tracking for Vue — session replay, console + HAR (2026)

Vue 3 reactivity is elegant when it works and quietly wrong when it does not. The most common bugs in Vue apps fall into two buckets: reactivity bugs (you mutated a ref directly, you destructured a reactive object, you assigned a new array instead of mutating in place) and lifecycle bugs (you set up a watcher and forgot to stop it, you read `$refs` before the component mounted). Neither shows up in a screenshot.

A useful Vue bug report includes the component name (because Vue's dev tools surface a tree, not a tag soup), the reactive state at the moment the user noticed the bug, and the network payload that triggered the reactive update. BugMojo captures the DOM + console + network — and Vue's dev-mode warnings are loud, so the report usually carries the answer in the console.

This guide is the practical bug-reporting handbook for Vue teams in 2026 — Composition API, `<script setup>`, Pinia, and Nuxt.

Framework-specific failure modes engineers actually ship through. Each is hard to spot in a screenshot and obvious in a session replay.

Real Vue bug patterns — the symptom you will see in a report and the fix that actually works.

Reactive Map / Set values do not trigger re-renders

Symptom: You add an entry to a `reactive(new Map())` and the UI does not update.

Fix: Vue 3.0–3.4 had partial Map/Set reactivity; 3.5+ fixes it but you must use `reactive()` not `ref()`. Upgrade if you are below 3.5, OR use a plain object keyed by string.

Template ref is null on first render

Symptom: `templateRef.value` is null inside a function called from `onMounted`.

Fix: Refs are populated synchronously on mount, but ONLY for elements present on the initial render. For elements rendered conditionally, use `nextTick()` or `watch` on the condition.

v-model on a custom component does not update parent

Symptom: Typing in a child input does not update the parent's state.

Fix: The child must emit `update:modelValue` (or your custom prop name). In `<script setup>`, use `defineModel()` (Vue 3.4+).

The honest comparison — where BugMojo wins, and where another tool might serve you better.