I'm having the same problem. My specific example is the word "box" when followed by a "?". If I add a space before the "?" or change it to a ".", it is no longer marked as misspelled.
I'm on a MacBook Pro with Catalina 10.15.7

Is this Hunspell, Proximity or both?

Also just saw this issue. Wrote "promp," spellcheck corrected to "prompt" and ate the comma.

(on Windows)

I posted about this in the community boards—same issue. Except I have also had an opening quotation mark picked up too. For instance, Check Spelling asks if I want to correct "the to the. See screenshot. (Also Mac OS Catalina 10.15.7 on a MacBook Pro.)

It’s actually grabbing all punctuation except periods: close parentheses, colons, dashes, etc.

When running a spell check in InDesign 16.0, punctuation is being included as part of a word, rather than a separate element. This is causing duplicate flagging (e.g. "Easveld" and "Easveld," register as two separate spelling errors) and I am also unable to add a word to my dictionary in these instances because it wants to add the word with the punctuation, which is not allowed.

To reproduce the issue, include a word that is not in the dictionary followed by a space, as well as the same word followed by a punctuation mark other than a period (e.g. comma, parentheses, etc). When you run the spell check, the word will come up in two instances, instead of recognizing both instances as the same spelling error. This causes the Ignore All function to skip the instances with or without punctuation, depending on which instance you are dealing with. This also blocks the ability to add a word to the dictionary if the only instance in the document is followed by a punctuation mark other than a period.

Note: I use spell check in InDesign quite frequently and have never come across this issue before.