Duplicate Symbols showing in 'Let me choose...' dropdown list - resulting in Missing Symbols

[nickywalsh]

Thanks for creating a great plugin!

I'm experiencing issues where I get Missing Symbols after using Symbol Swapper (no matter whether I use 'by name', 'by ID' or 'Let me choose...')

I've copied an artboard from a separate file into my master file. As a result, one or two new symbols appear locally in this new file, even though they are Library symbols.

When I use Symbol Swapper to replace these new (duplicated) symbols with the original symbols from their Library, the result is that when I view the instance of these symbols, I get the red error and "Symbol missing" message.

Interestingly, in the 'Let me choose...' dropdown list, there are multiple versions of many symbols:

However, if I try to insert a symbol from this library, I can see that there are no duplicates in the actual library itself:

Are you able to shed any light that may help me to resolve this issue?