I think it's because my primary chars chests are full. Also, this item was sent by a secondary character to Homestead.

Related questions, what happens to sent items when primary character chests are full? What happens to items sent by Madora or Jahan?

I don't know what the storage limit is, but only your two main character can send items to Homestead. Each character sends items to their own unique chest, and since Madora, Jahan or any other's don't have a chest, you will probably loose those items... don't do it.

There is a chance the item sent to the homestead by a follower will go in the chest of the character that recruited them, who they are the henchmen of

If the chests are full...supposedly it shouldn't allow you to sent items any more, but if it does check out all the possible chest and drawers, perhaps it's being put there

Items (currently) continue to be added to the chest after the limit of the UI to view the items has been reached (the chest isn't actually 'full'). You can use the 'take all' button to get things back that you can not see.

Items sent to the homestead by companions or henchmen are placed in one of the two chests.

Okay, good to know, thanks everyone.