In Poland the Art. 292 of Criminal Code and Art. 122 of Misdemeanor Code says something like "an item, about which on the basis of accompanying circumstances should and may be suspected that it has been procured by an illegal act" and directly addressed accidental fencing of an item (Art. 291 and 121 respectively address intentional/knowingly fencing an item).
I have no idea how that works in practice but googling "accidental fencing" in Polish ("nieświadome paserstwo") brings up a few results about people who bought cheap stuff online and it turned out to be stolen.
Here's one case like that with a lawyer's answer/opinion if you want to try Google page translate or can read Polish: https://www.eporady24.pl/nieswiadome_paserstwo,pytania,6,64,...