Well, to add some color, in most cases, the Recycle stage is used to park people who have been MQLed and then sent back/turned back by the LDR team as they didn't show the requisite interest. I haven't seen users assigning people who are flowing through the lifecycle model for the first time to the Recycle stage. Additionally, in most cases, this is a temporary stage before adding people back to the lead nurturing. To answer your question, it really is a process question as to whom you assign the recycled leads, you can either keep them assigned to the sales user who recycled those or even better and cleaner re-assign them to the generic Marketo Sync user. IMO whichever route you follow, it's important to have your marketing and sales team aligned and in agreement with it and follow the same consistent process for all the applicable Recycle records.