Cells duplicates and deletions

[alngrw]

Describe the bug

Cells dupcilate by themselves; usually it goes with the fact that some of them get deleted as well. On the screenshot you can see that some markdown cells got duplicated, some of them with and some without code belonging to the markdown.

Will you submit a PR?

• [ ] Yes

Environment

{
  "marimo": "0.16.5",
  "editable": false,
  "location": "/home/ec2-user/marimo-dev/.venv/lib/python3.13/site-packages/marimo",
  "OS": "Linux",
  "OS Version": "6.1.134-152.225.amzn2023.x86_64",
  "Processor": "x86_64",
  "Python Version": "3.13.4",
  "Locale": "en_US",
  "Binaries": {
    "Browser": "--",
    "Node": "--"
  },
  "Dependencies": {
    "click": "8.3.0",
    "docutils": "0.22.2",
    "itsdangerous": "2.2.0",
    "jedi": "0.19.2",
    "markdown": "3.9",
    "narwhals": "2.6.0",
    "packaging": "25.0",
    "psutil": "7.1.0",
    "pygments": "2.19.2",
    "pymdown-extensions": "10.16.1",
    "pyyaml": "6.0.3",
    "starlette": "0.48.0",
    "tomlkit": "0.13.3",
    "typing-extensions": "4.15.0",
    "uvicorn": "0.35.0",
    "websockets": "15.0.1"
  },
  "Optional Dependencies": {
    "altair": "5.5.0",
    "duckdb": "1.4.0",
    "nbformat": "5.10.4",
    "openai": "2.1.0",
    "pandas": "2.3.3",
    "polars": "1.34.0",
    "pyarrow": "21.0.0",
    "loro": "1.8.1",
    "ruff": "0.13.3",
    "sqlglot": "27.20.0"
  },
  "Experimental Flags": {
    "inline_ai_tooltip": true,
    "rtc_v2": true,
    "table_charts": true
  }
}

Code to reproduce

No response

[mscolnick]

@alngrw - likely because rtc_v2. can you turn this off and let us know if the issue persists?