World /Temp/Untitled_1.Untitled not cleaned up by garbage collection!

Context

I’ve been working within the shooter game since 4.9 but most of the source has been maintained by me since 4.12, meaning I’ve been updating code to get the game to work one version after the other until now.

Issue

I’ve encountered an issue, possibly from me, possibly from the upgrade from 4.18 to 4.19 (not sure), where the game crashes going from in game as the host to the main menu with the following log details hatebin

Client does not have this issue.

What I’ve done is gotten the latest shooter game 4.19 and updated any related code to how they do it just to try and minimize difference since their 4.19 version of the shooter game does not have this issue.

I’m confused because I have no map titled Untitled_1.Untitled and don’t know how or why UE4 resorted to using it? Perhaps its a fail safe thing or standard way of crashing?

I’m running out of ideas to sort this one out so resorting here.

Have the same issue on 4.26. The game crashes on startup with the following logs:
logs
and the following stack trace:
stack