Prefab variants dramatic increase in size due to duplicate data getting serialized

Has anyone encountered the issue where their prefab variants slowly increase in size due to data being duplicated in the variant? A prefab variant that starts off as a couple of kb can slowly increase in size over time until it is in the mb range in size.

When opening the prefab and inspecting the yaml there are hundreds of duplicate entries. The most common duplicate entry is the m_RootOrder property that gets serialized for any gameObject. (But sometimes other data gets duplicated as well).

It is possible to manually remove the duplicate data (although it can be a bit tedious). But over time the duplicate data reappears.

 

@SteenLund Currently I am using 2019.3.3f1, but I've seen the issue previously with 2018.4.11f1. Yes, the duplicates are identical in both field and guid. typical example from the prefab variant would be something like:

- target: {fileID: 1216425444298024552, guid: 53bd3e0f187988a479e5881cb07d25c0,
type: 3}
propertyPath: m_RootOrder
value: 12
objectReference: {fileID: 0}
- target: {fileID: 1216425444298024552, guid: 53bd3e0f187988a479e5881cb07d25c0,
type: 3}
propertyPath: m_RootOrder
value: 12
objectReference: {fileID: 0}

Everything is identical and it can be hundreds of entries of the same prefab override.

The prefab is checked into source control. The main reason we notice it is that the prefab variant can get extremely large in size. it happens slowly at first, so it is hard to notice.

 

@SteenLund Marvelous! That is great news! We are upgrading to 2019.4 soon.

Thank you.