When exiting the lab, factorio crashes and this error message appears:

The mod The Blueprint Designer Lab (1.0.3) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event BlueprintLab_design::on_gui_click (ID 1)
LuaEntity API call when LuaEntity was invalid.
stack traceback:
[C]: in function 'index'
__BlueprintLab_design/scripts/logic.lua:88: in function 'ToTheWorld'
BlueprintLab_design/scripts/logic.lua:9: in function 'OnLabButton'
BlueprintLab_design/scripts/gui.lua:46: in function <BlueprintLab_design/scripts/gui.lua:44>

This happened to me for no reason at all. Was designing a blueprint in the morning and when exiting in the evening now I can't. I've tried restarting, removing the mod and loading autosaves but nothing works. Please help, I can't continue playing anymore since I am stuck in the lab!!

I am aware this question has been asked by another user beforehand, but that post from almost 2 years still hasn't gotten an answer!! The factory must grow and I can't!!

This mod is essentially deprecated. This bug, plus many others, I have addressed in my own modern successor: https://mods.factorio.com/mod/BlueprintLab_design/discussion/6246456ed1702e6bed9195a3