[0.17.4] Text "LowLevelFatalError ... " appeared when pasting into train station name input field

[Impatient]

- I was playing a redmew scenario multiplayer game

Well, I did a lot of things, but related to train stations? ...

- I built a train station and named it
- I copied its name to reuse it later (i marked the text in the name input field and pressed CTRL+C)
- I remember the cursor turned into a copy symbol (like when you press CTRL+C to copy entities) for a short while
- Then I did other stuff ...
- Then I built another train station
- Then I clicked in the name input field of that station and hit CTRL+V
- Then this text, which looks like an error message, appeared in the name input field.

LowLevelFatalError.jpg (27.54 KiB) Viewed 1467 times

- The game did not crash or anything
- I typed the desired name into the field and kept playing for hours more

- I could reproduce the copy symbol to appear. When the station name input field is open and editable, click outside of the window on the game world (the window loses focus) and press CTRL-C (the copy symbol appeares).

factorio.EntityCopy_on_windows_lost_focus.png (97.2 KiB) Viewed 1431 times

- I could not reproduce anything other than this. Neither with the save of another singleplayer game nor with a save of that multiplayer game, when I left it hours later.
- Here is a link to a save of the game - but from the time I left it: https://we.tl/t-iaemI6jD4v

[Impatient]

I updated this bugreport with a link to a later save of the game. It is a redmew scenario game. The scripts might be of interest.
https://we.tl/t-iaemI6jD4v

[Impatient]

- I could reproduce the copy symbol to appear. When the station name input field is open and editable, click outside of the window on the game world (the window loses focus) and press CTRL-C (the copy symbol appeares). factorio.EntityCopy_on_windows_lost_focus.png

Updated OP with the above information.

Updated title to be more accurate.

[posila]

Thanks for the report.
I was not able to find "LowLevelFatalError" in our code, or any of libraries we use, nor have I been able to find a way how it could be generated during clipboard paste processing. Google search makes it seem it is something Unreal Engine uses in its logs (Factorio is not built on Unreal Engine), so it remains mystery why it would appear in your clipboard while playing Factorio.