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I presume you are referring to the Auto Fill feature? In general it seems to be working as expected. Here's a test form you can check on my end: https://form.jotform.com/61661105151949. It is possible that it is related to the quotation marks I mentioned earlier on the other thread post that you have. The form is actually deformed and preventing the validation to work when submitting it, so it is highly possible that the auto fill feature is also affected. You can try editing your form and removing the quotation marks on the column headers on your matrix field, then test the form, see if the auto fill feature is working after that.
Let us know if you need more help on this.