Hey, thanks for the report.
This is a known issue, and the team is already working on a fix. In a recent update, the Ask mode system instructions were changed so models no longer include file paths in code blocks, and because of that Apply doesn’t work.
Related reports:
About the streaming errors, this is caused by rate limits on the Gemini API side. If you use your own API key, the limits depend on your Google Cloud plan.
Unfortunately, the workaround using formatting rules for code blocks doesn’t work right now because it conflicts with the system instructions. Until a fix is shipped, the only options are to use Agent mode or copy the code manually.