Can you please post your form or at least a screenshot of your form hierarchie and the script your using to show/hide the comments?
the problem is that you're using a SOM expression beginning at the root object for your form.
As the PDF viewer interprets every object without an explicite accessor as the first instance your script points alsways to the first instance of a repeatable object.
xfa.form.form1.Inspection.FireExtinguisherInspection... is interpreted as xfa.form.form1.Inspection.FireExtinguisherInspection...
As the comments objects are located in the same level you can use a much shorter SOM expression, that is interpreted as a relative path.
UnubstrucetedComments.presence = "invisible";
Thanks! This worked perfectly....saved me so much frustration