Worked on the mautic/mautic repository to stabilize lead segmentation by addressing complex date filtering scenarios in PHP. Focused on backend development and testing, the work involved resolving a TypeError that occurred when using three or more OR conditions with date filters. The solution separated date-type filter handling into the ContactSegmentFilterFactory, eliminating segmentation crashes and ensuring accurate campaign logic. To reinforce reliability, a functional regression test was introduced, validating that segments with multiple OR’d date filters correctly include or exclude leads based on date_added. This approach improved test coverage and strengthened the verification workflow for segmentation updates in production environments.