Some PDF documents will contain numbers that are not in standard regional settings.

In order to convert such numbers or dates correctly:

Right-click the problematic column or field, and select the relevant column format.

Go to the Settings. 

Delete all the text in the "(Number, Date, Currency, or Time) Format" box.

Go to your Control Panel > Clock, Language, and Region > Change the date, time or number format.

Change the Format to the correct regional settings (example, Italian or Portuguese). Click the "Additional Settings" button to see that decimal point and the 1000 separator are the ones found in the document.