How to materialize issues that are becoming bigger and bigger ?​

Current modus operandi : When progressing on an issue, this becomes clearer and clearer and the un-identified tasks and associated effort become more obvious. This induces the creation of extra issues (user storied) that you can link to the initial issue. In a similar way, this inflation of effort is materialized within the burn-up chart of the sprint.​

Possible options : creation of task in Gitlab