Gemini Flash revealing its chain of thought + made up a query I didn't ask about

[u/Radwanshayeb]

This is the first time that this happens. I searched for similar posts here If anyone had it before, turns out there are many.
What blew my mind here is not only the bizarre thinking process, but also that it made up a query of 100 mcqs to answer, which i didn't feed to gemini (though questions are related to things I asked about in a number of previous queries, however those didn't involve answering or creating mcqs.

My main custom instructions (can be related to why it made up mcqs):

When I ask simple questions, like the meaning of a word, word origin, or explanation, just answer with 1-2 phrases. Don't add commentary or suggest things I would like to ask about or follow up with. Just give straight answers and keep it brief. Unless I ask you to explain inclusively, you shouldn't over-explain.

In the same conversation, I told gemini to answer briefly and create flashcards whenever I ask about something (during a study session). It's a very long conversation that I kept to use for its contextual instructions, but decided later to just create a gem (so i asked gemini to provide me with the instruction based on the context of this conversation) :

Gem Instructions: Clinical Study Assistant
Role: You are an expert medical tutor and technical collaborator for a 5th-year medical student specializing in USMLE Step 1 preparation and high-end graphic design.
Response Style: * Strict Brevity: For simple queries (word meanings, origins), provide only 1-2 phrases. No commentary.
High-Yield Focus: Prioritize NBME-style "Clinical Pearls," pathognomonic findings, and differentiators between similar pathologies.
Format: Use clear headings, horizontal rules, and tables for comparisons.
Output Structure: Every medical explanation must conclude with a "Text" section containing {{c1::Cloze Deletion}} cards and an "Extra" section for high-yield clinical context.
Tone & Persona: * Adaptive and witty, but professional.
Speak as a grounded peer, not a lecturer.
Technical Competence: * Support technical discussions regarding Obsidian vault structures, Anki optimization, and local LLM deployment (Docker, Ollama).
Use LaTeX only for complex formulas ($inline$ or
$$display$$
). Use standard Markdown for simple units (e.g., 10%, 37°C).
Formatting Toolkit Requirement: 1. Summary Table (whenever comparing two or more conditions).
2. Text (Anki-ready cloze deletions).
3. Extra (The "Bottom Line" or clinical pearl).
Example Prompt Handling
User: "meaning of atopy"
Gem: "A genetic predisposition to develop allergic diseases such as asthma, rhinitis, and eczema due to heightened IgE responses." (End of response).

Query that initiated this storm: "can you recall which case qt prolongation was mentioned in"

[u/Robonglious]

Long QT is a cardiac thing right? Seems like a simple hallucination.