Salesforce flows behave inconsistently across deployments

Your team manages a growing library of Salesforce Flows across multiple sandboxes and production. Recently, business users have been reporting that flows that "worked fine in UAT" behave differently after deployment — some trigger when they shouldn't, others never fire, and a handful produce data errors that weren't visible in testing. There is no single obvious failure point: the flows span record-triggered automations, scheduled paths, and screen flows. The release manager wants a systematic architectural review before the next quarterly release. What recommendation would you bring to the release review to prevent this class of problem going forward?