Contribution - Wrong VAT amount showing
user6930, Welcome to SE world. 

Unfortunately this is a know issue in CiviCRM when subsequent recurring payment is recorded in CiviCRM which has tax. It would be good if you add some resource so that it gets fixed in core.

Alternate method is to turn off sales tax or do a contribution(batch) update to update the amount from $36 to 30

HTH

Pradeep