The problem you described can be caused due to the inheritance the templates layout.
When you create a new template (2 columns) and put into it a repeater which uses news items from another path, then this items inherit the layout from their parent. You have now two options:

1. Save the 2 columns template as a new template Edit->Properties->Template -> Save as a new template. After the saving go to the news items which are placed under another parent and go to Edit->Properties->Template -> Select tepmlate and select the freshly saved template and click to inherit. Please do not forget to set the right path in your news repeater in the 2 column template to the another parent, where the items are placed. For example your template name is TwoCols and the news items are placed under Items template, so the content path in the repeater should by like /Items/%.

2. You can place all your news items under the 2 columns template, they should automaticly inherit the templates layout, but please make sure that it happens (Edit->Properties->Template). Maybe there can by string like "ad-hoc some numbers and characters", so please go to the end a make sure that there is "(inherited)", if no, you will also see a link to inherite below.