Widget Configuration Intent: Multi-select parameters fail with "unknown error" during ~0.5s initialization window

I'm experiencing a (probably) timing-related issue with WidgetConfigurationIntent multi-select parameters in my iOS widget extension. When users open the widget settings and tap on multi-select dropdowns within a specific ~0.5 second time window, they receive an error: "The action could not be completed because an unknown error occurred."

Reproduction Steps:

1. Open widget settings screen (long-press widget → Edit Widget)
2. Wait approximately 0.5 seconds after the screen opens
3. Tap on any multi-select parameter
4. Error appears

Timing Observations:

• < 0.5 second: Tap has no effect, widget does not react  (this is expected behavior, not the bug)
• ~0,5 second: Error occurs consistently
• > 0,5 second: Works perfectly, modal opens as expected

What I've Observed:

• Single-select parameters always work fine
• The error occurs regardless of whether the parameter options are static or require data fetching
• Both affected parameters display their options in a modal sheet (multi-select UI)

The specific ~0.5 second timing window strongly suggests this is related to the widget extension's initialization or warm-up process. It appears that during this brief window, the multi-select parameter handling is in an unstable state, while single-select parameters remain unaffected throughout.

• iOS 26: Successfully reproduced on both Simulator and physical device
• iOS 18: Could not reproduce the issue, multi-select parameters work consistently

Question:

Has anyone else experienced this issue with multi-select AppIntent parameters? Is this a known limitation during widget extension initialization, or is there a recommended approach to ensure the extension is fully ready before allowing parameter interaction?

I've tried testing other apps' widgets with multi-select parameters but haven't found any examples to compare against. Any insights or workarounds would be greatly appreciated!