When submitting a survey created in ArcGIS Online and shared with a Collaboration group with Portal for ArcGIS in the Survey123 Field app using a Portal for ArcGIS connection, the error, "Invalid Token" is returned.
Cannot reproduce with a 'Copy (if possible}' collaboration using ArcGIS Enterprise 10.8 and ArcGIS Online. The invalid token error likely indicates that the feature service was not able to be copied; in that situation, it will be copied over as reference (and still have the original ArcGIS Enterprise URL).