Since Avatar SDK version 3.5.2, and including 3.6.0, whenever the Builder tab is visible and clicked, or every few seconds, Unity lags heavily and pops up a window indicating asset importing.
The amount of lag is proportional to the number of avatars in the scene.
Through investigation I've found that this is a result of a call to the method "ValidationEditorHelpers.CheckIfUncompressedAssetBundleFileTooLarge" that is made from the "OnGUIAvatarCheck" method in the "VRCSdkControlPanelAvatarBuilder" class.
Specifically, it is the second call to this method that happens without the use of the "vrcFilePath" variable.
This call seems to cause a new file to be created in the project's assets folder for each avatar in the scene, which Unity attempts to import. Each import causes further lag to the Unity editor, and when there are too many avatars this causes the loading var to pop up which blocks any input to the editor.
This is highly disruptive to my ability to work on avatars.