Extension for PIP application

I was awarded DLA indefinitely 16 years ago, a few months back I was invited to apply for PIP, I rang them, started the application process and had to wait 5 weeks for the application to arrive. On the letter it stated that I had to submit my application by a certain date, this was in 2 weeks time, or my DLA would stop. 5 days before the deadline I received a letter form the DWP advising me that as they hadn’t received my application they were extending the deadline by 2 weeks. I hadn’t asked for this extension so thought it was very odd. Is she this standard? Do they extend the deadline even though I hadn’t requested an extension?

Thanks for your quick reply, is this at risk of not being awarded PIP? Many thanks