JSX Script Hangs on executeAction for "Define Pattern" with 300DPI JPEGs

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I am developing a batch processing script for Photoshop (v25.x). The goal is to take 100 JPEGs (6x6 inches, 300 DPI) and apply them as a Pattern Fill Adjustment Layer inside a nested Smart Object structure (Main PSD > Level 1 SO > Level 2 SO > Pattern Fill Layer).

​The Issue:

The script successfully opens the JPEG, flattens it, and performs selection.selectAll(). However, it consistently hangs (Photoshop becomes unresponsive with 'marching ants' visible) when executing the ActionDescriptor for 'setd' (Define Pattern).

​What I've Tried:

• ​Setting app.displayDialogs = DialogModes.NO
• ​Using app.purge(PurgeTarget.ALLCACHES) between iterations.
• ​Flattening the source document before defining the pattern.
• ​Hardcoding the pattern name to avoid naming conflicts.
• ​Running with GPU Acceleration disabled.

​The Question:

Is there a more robust way to define a pattern from an open document that avoids the UI-thread hang, or is there a way to implement a 'Wait/Sleep' state in JSX to allow Photoshop to finish the pattern registration before the script moves to the next executeAction?

​Environment: Windows!--endfragment>