"The 15 digit case-sensitive version is referenced in the UI and also visible in the browser. while the 18 digit case-insensitive version is referenced through the API. The last 3 digits of the 18 digit Id is a checksum of the capitalization of the first 15 characters, this Id length was created as a workaround to the legacy system which was not compatible with case-sensitive Ids. The API will accept the 15 digit Id as input but will always return the 18 digit Id."
This isn't something HubSpot is responsible for, nor is it something that should have any impact with syncing data. Additionally, the SF Account ID is a ready only property in HubSpot, as we retrieve this data from Salesforce. It can not be edited.
"The 15 digit case-sensitive version is referenced in the UI and also visible in the browser. while the 18 digit case-insensitive version is referenced through the API. The last 3 digits of the 18 digit Id is a checksum of the capitalization of the first 15 characters, this Id length was created as a workaround to the legacy system which was not compatible with case-sensitive Ids. The API will accept the 15 digit Id as input but will always return the 18 digit Id."
This isn't something HubSpot is responsible for, nor is it something that should have any impact with syncing data. Additionally, the SF Account ID is a ready only property in HubSpot, as we retrieve this data from Salesforce. It can not be edited.