Event Definitions get stuck and not triggered with no logs

## Expected Behavior
Event Definitions are running as configured (every 5 mins for example) and generating notifications, with no delay

## Current Behavior
Event Definitions are not running as configured (every 5 mins for example) and not generating notifications, with delay keeps growing and eventually after several graylog restarts "Next Timerange" is empty

## Possible Solution

Not found

## Steps to Reproduce (for bugs)
1. Start Graylog Cluster
2. Expect event definitions to run
3. Fail

## Context
All of my event definitions are stuck now. There is no MongoDB or Graylog errors present in containers stdout

## Your Environment

* Graylog Version: 6.3.15 Docker Container Official
* Java Version: Bundled
* OpenSearch Version: 2.19.5
* MongoDB Version: 7.0
* Operating System: Ubuntu 22.04
* Browser version: Google Chrome Latest

## Checklist
[] This issue fix need to be backported.
[] Does this issue have **security** implications?

Start by reproducing the stuck Event Definitions in a Graylog 6.3.15 Docker cluster using the reported MongoDB 7.0 and OpenSearch 2.19.5 environment. Compare the configured schedule, growing delay, and empty “Next Timerange” across restarts, then confirm that definitions run on schedule and generate notifications without errors.

Written by the indexing model from the issue text.