[Bug Report] Multi-turn fails with 'Invalid thought signature' when both Search and Maps Grounding are enabled

Environment:
- Platform: Google AI Studio
- Model: Gemini Flash Latest
- Tier: Free Tier
- Tools Enabled: Google Search Grounding + Google Maps Grounding (Simultaneous)

Steps to Reproduce:
1. Select Gemini Flash Latest or 3.7.
2. Enable both Google Search and Google Maps.
3. Send an initial prompt requiring grounding/reasoning (e.g., “Find the coordinates of Manchester United’s new stadium”).
3.1. Turn 1 completes and renders output normally.
4. Send a follow-up prompt in the same session (e.g., “When will it be finished?”).

Observed Behavior:
The request immediately fails on the second turn with the following error banner/output:

[original: beyond::dependency::INVALID_ARGUMENT] Invalid thought signature. (qos=CRITICAL_PLUS)

- The multi-turn conversation cannot proceed further.
- Resetting/starting a new session with the exact same dual-grounding setup reproduces the error on the second turn.

Additional Comment:
- This workflow (Search + Maps grounding in multi-turn) was working as expected until a few days ago.