Constrained SP: Pre-build not happening even when earlier buckets have available capacity

Summary:

I am testing constrained planning behavior with weekly buckets (Monday start), using a 5-day × 8-hour resource calendar (excluding Japanese holidays).

Item FG requires resource R1 for 3 days (24 hours), and its component, SubAssy requires the same resource for 1 day (8 hours).

When I create demand for 7 units of FG in the week of June 5, FG planned orders are generated as shown in the table (8th row).

My understanding is that dependent demand for SubAssy is generated in the same buckets, and pre-build should then be applied considering capacity constraints.

Since the resource R1 is fully utilized by FG from May 18 onward (10th row), I expected SubAssy to be pre-built into earlier weeks where capacity is available (row:12 to 14).