User Profiles Synchronization Error Event id 5553 - Every hour

Second Event: (although we don't always get this error with the one above)

failure trying to synch site 6c02f82c-2029-4ca0-990b-d14786b95d88 for ContentDB 8185106e-233e-4302-bbc5-d0fb2252c64a WebApp 2b659ceb-e7b4-46d4-b2a1-1a9679a357c3. Exception message was Cannot insert duplicate key row in object 'dbo.UserMemberships' with unique index 'CX_UserMemberships_RecordId_MemberGroupId_SID'.

The statement has been terminated..

Does anyone know why this is happening and how it can be fixed?

failure trying to synch site a12d2e6b-8227-45cd-b232-594f70d1abd1 for ContentDB 1fa8ce0f-f219-4f43-af9f-c5dc57257f4d WebApp 54c24445-8543-493c-857b-5a57df27c722. Exception message was Procedure or function profilesynch_MS_DeleteWeb has too many arguments specified.

The 'profilesynch_MS_UpdateWeb' procedure attempted to return a status of NULL, which is not allowed. A status of 0 will be returned instead..