A device may receive a manifest that identifies a plurality of content fragments associated with a content asset. The device may receive or access instructions for inserting secondary content into a location of the content asset that does not align with the boundaries between the content fragments. Based on the received instructions, the playback device may generate updated manifest information that identifies a first modified content fragment and a second modified content fragment. The location for inserting the secondary content in the updated manifest information may align with a new boundary of the first modified content fragment or the second modified content fragment. The device may share the updated manifest information, and may receive a modified manifest file, or content asset, comprising the modified content fragments.