Harness status: Error

Uncaught TypeError: Cannot read properties of null (reading 'split')

TypeError: Cannot read properties of null (reading 'split')
    at parseKeylist (https://xn--n8j6ds53lwwkrqhv28a.wpt.live/fenced-frame/resources/utils.js:188:18)
    at https://xn--n8j6ds53lwwkrqhv28a.wpt.live/fenced-frame/resources/background-sync-inner.https.html:11:42