Did you print and mail your return and forget to include form 8889?
Then if you have any indicators for an active HSA (like code W in box 12 of your W-2), then yes, the IRS will send you a letter (I have seen this letter).
In a normal year, this IRS letter might take 3 or so weeks - but this is not a normal year.
But since you don't want to change your return but just add a form, amending might cause more harm than good, in trying to explain why you are amending the return when no numbers changed.
Just wait for the request for the 8889, and send it then per the instructions in the letter.
If you e-filed, then I don't understand why you think the 8889 is missing.
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