OriginTrial enablement for 'WebAssembly JSPI' seems to fail in ServiceWorker

[rentallect]

Although setting the meta http-equiv="origin-trial" content="<MYTOKEN>" does succeed in turning on the JSPI flag in the page...

...If I attempt to load WASM that requires JSPI in the ServiceWorker my page registers, I get the familiar WebAssembly.Function is not a constructor error (as though the JSPI flag wasn't enabled).

Is there something additional that needs to be done during SW registration to inform that side that JSPI is indeed supposed to be enabled?