Hi Clofly,
Thank you for the hint. Now I can trace the plugin log based on plug-in MktActivityCreatePostEventPlugin.
Btw, plug-in MktActivityCreatePostEventPlugin is enable in our instance:

As what I investigate,
The plug-in Microsoft.Dynamics.Crm.MarketingPlugins.Plugins.Data.MktActivityCreatePostEventPlugin throw the error. Here the error message:
Message: Exception 'InvalidPluginExecutionException' occured: The PhoneCall (Id = 114a6f18-576a-465a-a01b-f1d7cabc3291) in the "msdyncrm_msdyncrm_customerjourneyiteration_phonecall." relationship with the msdyncrm_customerjourneyiteration (Id = 7b25049f-b2b2-4f33-ace6-076f76fc53a2) doesn't exist.
Here the trace log on the plug-in :
2019-09-10T03:04:31.9668547Z :: Converted to list, element count is 1
2019-09-10T03:04:31.9668547Z :: Marketing activity token: CampaignCreateActivityEntity
2019-09-10T03:04:31.9824777Z :: [CampaignCreateActivityEntityAction]
2019-09-10T03:04:31.9981142Z :: Finished processing PhoneCall activity.
2019-09-10T03:04:32.5606065Z :: Entity field name activitytypeid does not match CRM entity field name.
2019-09-10T03:04:32.5606065Z :: Entity field name title does not match CRM entity field name.
2019-09-10T03:04:32.5606065Z :: Entity field name isnamesystemdefined does not match CRM entity field name.
2019-09-10T03:04:32.5606065Z :: Entity field name name does not match CRM entity field name.
2019-09-10T03:04:32.5606065Z :: Entity field name activityitemid does not match CRM entity field name.
2019-09-10T03:04:32.5606065Z :: Entity field name templateentitylogicalname does not match CRM entity field name.
2019-09-10T03:04:32.5606065Z :: Entity field name tenantid does not match CRM entity field name.
2019-09-10T03:04:32.5606065Z :: Entity field name templateentityrecordid does not match CRM entity field name.
2019-09-10T03:04:32.5606065Z :: Entity field name msdyncrm_scheduleddurationminutes does not match CRM entity field name.
2019-09-10T03:04:32.7637381Z :: Logging exception with Message:The PhoneCall (Id = 114a6f18-576a-465a-a01b-f1d7cabc3291) in the "msdyncrm_msdyncrm_customerjourneyiteration_phonecall." relationship with the msdyncrm_customerjourneyiteration (Id = 7b25049f-b2b2-4f33-ace6-076f76fc53a2) doesn't exist.
2019-09-10T03:04:32.7793647Z :: Couldn't udpate activity msdyncrm_mktactivity with ID 40852fb1-77d3-e911-a812-000d3a07bbcc
2019-09-10T03:04:33.0293643Z :: Exception 'InvalidPluginExecutionException' occured: The PhoneCall (Id = 114a6f18-576a-465a-a01b-f1d7cabc3291) in the "msdyncrm_msdyncrm_customerjourneyiteration_phonecall." relationship with the msdyncrm_customerjourneyiteration (Id = 7b25049f-b2b2-4f33-ace6-076f76fc53a2) doesn't exist., CorrelationId: 2a434102-ebe2-42cc-b2e7-013a67c32c33
Is there something missing in phonecall propertise?