Two-column layout alternate of variables in the Service Portal does not match the same layout in the instance. The file "Two column alternate Instance" shows a header field followed by four fields in a two-column, alternating-side layout with two fields per column. In the Service Portal, it shows one field in the first column and three fields in the second column.

1. Add a Container Start / End to a catalog item.

2. Set the container to "2 sides, alternating".

3. Place four or more variables into the container.

   Notice that instead of the fields alternating, the first field is in the first column. The second, third, and fourth fields are in the second column.
   
   

The intent with Service Portal is to enable our customers to provide modern, easy-to-use, device agnostic experiences for their end users or requestors. We do not intend to provide full feature parity between the Platform experience and the Service Portal experience. However, we do understand that you may have built out catalog item forms that are fairly complex and do not render well in the Service Portal today.

Hopefully, the updates provided in the link below (also back-ported in Istanbul Patch 8) will help you overcome some of those challenges:

https://community.servicenow.com/community/service-automation-platform/blog/2017/05/05/service-catalog-on-service-portal

If they do not, the attached update set can be used to adds two new fields to the sc_cat_item table using iFrames but has changes that mask the iFrame experience.

Before using the update set, please understand:

• This approach is not a product offering, so it will be unsupported. It only provides an option that you can use, if you choose to do so.
• This is intended to be a short-term option so you can continue to use the Service Catalog on the Service Portal, while you set in motion plans to transform your catalog item forms to fit the Service Portal experience.

From Istanbul Patch 8 onwards, in terms of variable layout these is what would be supported for all future Service Now releases. There will be no farther support on any layout given to Service Portal hence forth. Service Portal will never support nested two column layout.

Please note there might be a further redesign in the current Service Catalog Item to take full advantage of the new portal layout architecture.