Start time bug in cumulative ExponentialHistogram

[aabmass]

Which problem is this PR solving?

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context. List any dependencies that are required for this change.

Fixes # (issue)

Short description of the changes

Type of change

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• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Test A

Checklist:

• Followed the style guidelines of this project
• Unit tests have been added
• Documentation has been updated

[codecov]

Codecov Report

Merging #3930 (ed49546) into main (19fb033) will decrease coverage by 1.74%.
The diff coverage is n/a.

❗ Current head ed49546 differs from pull request most recent head 45a0db4. Consider uploading reports for the commit 45a0db4 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3930      +/-   ##
==========================================
- Coverage   92.90%   91.16%   -1.74%     
==========================================
  Files         297       82     -215     
  Lines        8838     1800    -7038     
  Branches     1815      363    -1452     
==========================================
- Hits         8211     1641    -6570     
+ Misses        627      159     -468     

see 221 files with indirect coverage changes

[pichlermarc]

Fixed by #3934 🙂