Thanks to Hlodver - this is now fixed in the latest release of csound wasm/browser
https://cdn.jsdelivr.net/npm/@csound/browser@7.0.0-beta26/dist/csound.js
check it out - mp3-diskin by vlazzarini -p5.js Web Editor
So yes, if you’re using wasm, it’s time to move to Csound 7.0