This article articulates an error with the cut list mass properties that has been reported as a bug in 2018. At the moment, there is no workaround other than to manually change the cut list property. This article will be updated with the service pack of the version that resolves the issue.
In 2017 and earlier, if you placed Weight as a custom property of a weldment profile linked to mass, when it is inserted via structural member, the weight of the structural member is added to the cut list. In 2018, this same workflow shows the entire weight of the part, instead of the individual member. This is due to the syntax of how the cut list property is brought in, no longer referencing the structural member. See the images below:
The only workaround at the moment is to manually change the cut list property back. If you go to the drop down and select mass, it will revert back to the mass of the individual structural member:
There is a known issue that SOLIDWORKS is currently addressing in SPR #1067715. If you are experiencing this issue, please contact support and request to be added to this SPR. Additional hits will move it up the SOLIDWORKS priority, and adding yourself to the SPR will allow you to be notified when the issue is resolved.
You can either email us at Support@hawkridgesys.com or call us: (US) 1.877.266.4469 or (Canada) 1.866.587.6803