Error with project locator on a Non-standard WIP job

Existing Setup

We have discrete manufacturing implemented. Though we don't have project manufacturing, we use Seiban number functionality to attach project references to products for the purpose of achieving hard pegging in ASCP.

What we are trying:

We are currently exploring the non-standard WIP job functionality which we might use in one of our processes. After creating the WIP header without any assembly when we try to add components in the "Material requirements" form, we get below error if the supply locator has project number on it. The subinventory being used has locator control set as "Dynamic Entry" and also has the very specific project locator pre-specified. The locator is being used for other transactions since many years.