Created attachment 162396 [details] Mails threading correctly with the specific inbox selected SUMMARY Threading seems broken in the Unified Inbox but only there, at least for this specific group of messages. STEPS TO REPRODUCE 1. ??? OBSERVED RESULT Threading being the same in specific and unified inboxes. EXPECTED RESULT Threading differs. SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: (available in About System) KDE Plasma Version: 5.27.8 KDE Frameworks Version: 5.110.0 Qt Version: 5.15.10 ADDITIONAL INFORMATION Glad to help debug further; I have a .mbox of the mails on the screenshot, is sharing these risky in any way (e.g. personal data)? Maybe they could help reproduce the issue.
Created attachment 162397 [details] Mail thread being split in two in the unified inbox