The mod allows you to replace the Upcycler with a higher-quality variant, such as uncommon, but when you build over it with the higher variant, you get the error message:
The mod Upcycler (1.0.1) caused a non-recoverable error.
Please report this error to the mod author.
Error while running event upcycler::on_tick (ID 0)
LuaEntity API call when LuaEntity was invalid.
stack traceback:
[C]: in function 'newindex'
__upcycler/scripts/tick-handler.lua:92: in function 'handle_observed_struct'
upcycler/scripts/tick-handler.lua:136: in function <upcycler/scripts/tick-handler.lua:121>
It seems to happen only with the Upcycler itself; every other structure or entity I tried is replaced without issues. Something else of note when I deconstructed it was that it had items still inside, Utility Science packs. But even emptied out, the same error above applies.