Initially, I gave up on the issue and just left Live Coding on. But I recently stumbled upon a new problem with Live Coding and decided to revisit this issue and fix both of them. To gather more information on the issue I added more debug code to the failing line in UITag.h and found out the error was being thrown on a gameplay tag named UI.Action.Escape.
I started the project with the Lyra Example Project back when I was using the production packaged Unreal 5.3 (before moving to built from source) and the tags from the config files are the problem. Going into the Project Settings and disabling ‘Import Tags from Config’ in ‘GameplayTags’ solved the issue of the engine crashing when disabling Live Coding.
The project still doesn’t re-open after closing the editor, however. The second error is still there:
‘Fatal error: [File:C:\Users\ronis_1xgq\UnrealEngine\Engine\Source\Runtime\CoreUObject\Private\UObject\UObjectGlobals.cpp] [Line: 3337] Objects have the same fully qualified name but different paths. New Object: IndicatorWidgetInterface /Script/LyraGame.Default__IndicatorWidgetInterface Existing Object: IndicatorWidgetInterface /Script/LyraGame.Default__IndicatorWidgetInterface’
At this point it’s clear the LyraGame integration is messed up, I’ve noticed that the Unreal Engine built from source doesn’t match the version from the production-ready Engine. It always accuses a version mismatch if you try to use something built in one within another, so that might be it.