# Tag Historian Logs Duplicate Value After Gateway Restart **URL:** \ **Category:** Ignition\ **Created:** [July 13, 2026, 12:39pm UTC](https://forum.inductiveautomation.com/t/tag-historian-logs-duplicate-value-after-gateway-restart/116369 "2026-07-13T12:39:17Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [July 13, 2026, 1:00pm UTC](https://forum.inductiveautomation.com/t/tag-historian-logs-duplicate-value-after-gateway-restart/116369/2 "2026-07-13T13:00:17Z")
A gateway restart means there's a gap in Ignition's knowledge of what might have gone on while it wasn't paying attention. Recording the new starting value, even if duplicate, ensures accurate history from the starting timestamp forward. Related topic: > [@Memory Tag Value Changed Event Fires on Startup/Creation with initialChange=True and Uncertain\_InitialValue Previous Value](https://forum.inductiveautomation.com/t/memory-tag-value-changed-event-fires-on-startup-creation-with-initialchange-true-and-uncertain-initialvalue-previous-value/116248/2): > > Yes, to all. The initialChange flag means the infrastructure has had a gap in attention (long or short) and doesn't know, for sure, what the previous value really is. For memory tags, it is initialized from the value storage, but might be out of date. You are not guaranteed that the first "real" value change has initialChange false. No. For other than memory tags, previousValue is entirely null on startup/tag restart. Memory tags try to start up from value storage, if possible. You … --- _[View the full topic](https://forum.inductiveautomation.com/t/tag-historian-logs-duplicate-value-after-gateway-restart/116369)._