RichApi.Error: InvalidArgument

[sentry]

Sentry Issue: WORD-PLUGIN-10

RichApi.Error: InvalidArgument
  at new n (/lib/1/hosted/word-win32-16.01.js:25:269237)
  at i.processRequestExecutorResponseMessage (/lib/1/hosted/word-win32-16.01.js:25:333684)
  at None (/lib/1/hosted/word-win32-16.01.js:25:331747)
  at Z.invoke (/polyfills.696d58812e4a1097.js:3:19968)
  at Object.onInvoke (/vendor.d81c3635439bf08c.js:3:126295)
...
(8 additional frame(s) were not displayed)

[henih]

@lsmith77
It's not us, but Office.js - potential possible causes, but the error message is too vague to properly identify:
OfficeDev/office-js#3623
OfficeDev/office-js#1561