Slack alert was fired with hours of delay

### Environment

SaaS (https://sentry.io/)

### Steps to Reproduce

I'll share the details in the Jira ticket

### Expected Result

Slack alert should have arrived almost immediately

### Actual Result

Slack alert arrived hours later

### Product Area

Alerts

### Link

_No response_

### DSN

_No response_

### Version

_No response_

┆Issue is synchronized with this [Jira Improvement](https://getsentry.atlassian.net/browse/FEEDBACK-2270) by [Unito](https://www.unito.io)