Scheduled jobs are not running on time

I set cron string to */5 * * * * but the task is run nearly every 10 mins, contrary to what is defined as the minimum interval (5 mins).

Workflow file:

name: Run periodically.

on:
  schedule:
    - cron: '*/5 * * * *'

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
    - uses: actions/setup-node@v1
    - run: npm i
    - run: node index.js

Sorry for letting you suffering from this. This is a known issue. And I found an issue in our internal channel: due to the large number of scheduled jobs, It is beyond the current process rate of scheduled jobs. So there are some delay. Also we know that it bring significant pain for our customers. GitHub engineering team are working on a way to resolve this issue and improve schedule job behavior. Thanks for your understanding.

I mean, running every 5 minutes is fairly extensive. I am willing to bet they will end up making it a 15 minute minimum.