Steps to reproduce:

1. Create a custom SFX instrument.

2. Create an SFX using this instrument.

3. Add the latter SFX (but not the former) to a music pattern.

4. Select the pattern and copy.

5. In a new PICO-8 cart, select a pattern and paste.

Expected behavior:

All necessary data to reproduce the original pattern should be transferred. (Notably, this occurs when pasting into the BBS.)

Observed behavior:

The SFX instrument is not copied, and only the SFX specifically included in the pattern are copied.

to get your instruments back, u could just copy/paste the instruments into the same sfx slots in the destination cart. imo, this is the expected behavior, bc when u copy a music pattern to a different cart, it shouldn’t be able to accidentally wipe out existing sfx 1-8

Will gladly close the bug report if this is intended - I do understand the argument you are making that this is the case.

My expectation is that it would copy the custom instrument if there is room in one of the first 8 sfx slots.

@bikibird's suggestion would be consistent with how copy+pasting patterns is implemented otherwise: if there is room, data is copied, and if there is not, it is not. A more sophisticated solution might also automatically detect if an identical SFX instrument exists and reuse it if it does.

Thinking about it some more, while I see the justification for the current behavior, it does make it impossible to copy SFX from the forums that involves custom SFX instruments. You can test this quite easily with my Erik Satie - Gymnopedies 1 composition - because this is not a cart where you can select the SFX separately, there's no clear way to transfer the music back to PICO-8.