I moved one of the input actions in the player controller blueprint. It calls a custom event in the player character blueprint or the game mode blueprint depending on whether the character is dead or alive and it works fine in the editor viewport and new editor window. It is not working in a standalone game though.
All the bindings are set as default.
Managed to track the issue down to the function which restarts the pawn if it is dead. After some fiddling with it, creating a mirror function to test where it breaks, reconnecting the links to the input node on the old one, it now works.
I noticed that recompiling the player controller blueprint marked the game mode blueprint to be in need of recompiling and vice versa. This in combination with me having the automatic recompiling of blueprints turned off could be the cause of my issue.