Failed to parse argument

Recently I noticed the following lines in the output log window of the UE4.12 editor:


LogText:Warning: Failed to parse argument "GameModeName" as a number (using "0" as a fallback). Please check your format string for errors: "GameMode: Edit {GameModeName}".
LogText:Warning: Failed to parse argument "RootClass" as a number (using "0" as a fallback). Please check your format string for errors: "Select {RootClass} Class".
LogText:Warning: Failed to parse argument "GameStateName" as a number (using "0" as a fallback). Please check your format string for errors: "GameState: {GameStateName}".
...

Any ideas what these warnings could mean?

No ideas? :frowning:

I have them myself aswell. Probably some in-engine harmless bug.