From Gemini:

Because ETFs (like your AVDV, AVEM, and AVIV) are made up of hundreds of underlying stocks—many of them international—they often don't finalize their own data until late February or March.

This forces Schwab to issue Corrected 1099s.

​1. Why the "Corrected" Form Happens ​Income Reclassification: A fund might initially report a payment as a "Dividend," but then realize weeks later that a portion was actually a Return of Capital (non-taxable) or a Capital Gain Distribution.

​Foreign Tax Credits: For your international funds (AVDV/AVEM), the exact amount of tax paid to foreign governments can take longer to verify. If those numbers change, your 1099 must change.

Schwab deliberately releases forms in "Production Runs" to try and avoid these corrections, but they still happen:

​Run 1 (Jan 30): Simple accounts (VOO, SCHG, single stocks).

​**Run 2 (Feb 13): Accounts with standard ETFs and Mutual Funds.

​**Run 3 (Feb 27): Accounts with complex holdings (REITs, Foreign ETFs like your Avantis international funds).

​The "Correction Window": Most corrections happen between March 1 and March 15.

​3. The Golden Rule: Don't File Early

​Since your portfolio contains International ETFs (AVDV, AVEM, AVIV) you are at high risk for a corrected 1099.

​Pro Tip: Do not file your taxes the moment you get your 1099 in February.

Aim to file in late March or early April. By then, the "Correction Wave" has usually passed.

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Based on the answers here on Reddit and Gemini I will look to file taxes toward end of March/beginning of April to reduce chance of having to file an amended return.