I have also encountered such things for several interviews I have attended before.

They shortlisted me for interview and I attended the interview, after there's no response from the employer side and a few weeks later when their job openings in job portals expired they reposted their job openings again.

For one of the companies that I interviewed, I understood that they are undergoing a massive expansion at the moment so it might be possible that they might need many people for the position so they look for hires several months in advance.