Hi Petr,
Yes, I think so too, that the mapping records didn't exist when the conditions were downloaded. Typically, the CHANGED_AT date/time is updated in BUT000 when a master record is updated. You could check using PARTNER_GUID from CRMM_BUT_CUSTNO.
But to resolve these errors now, you'll have to download the conditions again to CRM.
Best regards,
Vijayalakshmi