Incorrect Issue Merging causing loss of Crash Visibility

### Environment

SaaS (https://sentry.io/)

### Steps to Reproduce

Sentry is incorrectly merging unrelated issues, resulting in multiple crashes with different call stacks being combined into a single issue. This behavior prevents also impacts our Jira integration, where merged issues fail to generate Jira tickets.

For details, please see the internal ticket.

### Expected Result

Sentry should not merge unrelated issues with different call stacks

### Actual Result

Sentry is merging unrelated issues with different call stacks automatically.

### Product Area

Issues

### Link

_No response_

### DSN

_No response_

### Version

_No response_

No file, test, or entry point is named. Start by reviewing the linked internal ticket and the issue-merging behavior, then reproduce the case with unrelated crashes and different call stacks; done means unrelated issues remain separate and Jira ticket creation is not blocked by merging.

Written by the indexing model from the issue text.