Chances are you will make payments to different servicers over the course of your VA mortgage. Selling mortgages from servicer to servicer is common, and sometimes a VA mortgage payment is sent to the old loan holder because notification of the new owner of your loan and your payment became crossed in the mail. If this happens, you may receive a notice of non-payment from the new loan holder.
Don't delay in contacting the new owner of your VA mortgage to straighten up the problem. While it is technically up to the two servicers to fix the matter, your credit rating and payment schedule could be affected if you don't act accordingly.