I have two projects setup in a new 17.1 instance, one is called /CoreLab and the other is called /Projects. The /Projects project contains workbook containers as its direct children. These workbooks contain samples submitted by end users. Once samples are entered into the project's study they "submitted" to the CoreLab container by inserted new samples into a sample set in /CoreLab called AccessionedSamples. This sample set has these fields:

Name: a Name Expression set to S${batchRandomId}.${yearlySampleCount}
SpecimenId: The original SpecimenID in the project (workbook container)
Project: The entityId of the project (workbook container) in the /Projects project.

When trying to make the sample set's Project field a lookup to core.Container by setting the lookup as follows:
    Folder: /Projects
    Schema: core
    Table: Container

It doesn't correctly do the lookup, but puts angle brackets around the entityId (e.g <eecab1a5-f241-1034-a3ab-97dc5b50629f>)

I can, however, successfully setup a list in /CoreLab which contains a field called Project which is the same lookup to /Projects' core.Container.