Not at all. It’s common practice to call former Presidents, Vice Presidents, Governors, etc, still by that title. Especially, the press does it.
I was on a Facebook thread right after the first debate where a woman was having a hissy fit that the moderator addressed Biden as Vice President Biden. She said it was insulting to Pence and saw it as some sort of Democratic conspiracy. I told her it’s common practice, and that she can just watch for it with both Democrats and Republicans and see it is not some sort of political partisan ploy, and she wouldn’t accept my answer.