Missed Form 8833 for 2025: wait for IRS response or file 1040-X?

Hi everyone,

I have a question about whether I should take any action after filing my 2025 tax return without Form 8833.

My situation:
I was at University X from January 2024 to October 2025 on J-1 Research Scholar status, paid from research grants. In November 2025, I moved to University Y, still on J-1 Research Scholar status and still paid from research grants. 

Two details that may matter:

• I entered the US in late December, 2023, so I believe I am a resident alien for 2025 under the Substantial Presence Test.
• I believe I qualify for benefits under Article 20 of the US-Italy tax treaty for 2025, since I came from Italy to conduct research at a recognized educational institution and my initial stay was expected not to exceed two years.

I filed my 2025 return claiming the treaty benefit, but I did not mail Form 8833.

I thought Form 8833 might not be required based on Publication 519, page 68, Exception 2, for students, trainees, and teachers, and I assumed a J-1 Research Scholar could fall under the “teacher” category for this purpose. However, I am unsure because my case is a bit unusual.

I was in the US for only a few days in 2023 and did not file a return for that year. I am wondering whether I should still have filed Form 8833 for 2025, possibly explaining my situation a bit better and mentioning Article 1(3)(b) of the treaty.

My main questions are:

1. If I missed Form 8833 for tax season 2025, should I wait to see whether the IRS accepts the return as filed with treaty benefits, or should I amend now with Form 1040-X and attach Form 8833?
2. If the IRS does not accept the treaty position, would the normal next step be? To respond to a notice or amend the return?
3. Do I need to file Form 8843 for 2023, since I was in the US from late December, 2023 to early January 1, 2024?

Thank you very much for any guidance.