Shortlisted for offer - am I the backup?

Some context - I’ve had a few rounds of interviews for this company - recruiter screen, hiring manager call (at the end of which I was told they’d select 4 candidates to the final round panel intervie

Some context - I’ve had a few rounds of interviews for this company - recruiter screen, hiring manager call (at the end of which I was told they’d select 4 candidates to the final round panel interview), then the final round. I did my final interview last Friday and was told they were wrapping up the others early this week. Fast forward to Thursday and I get an email that says they’re still deliberating on a decision and need a couple more days to decide, but that I’m on the shortlist of candidates they’re considering for the offer. It seems odd to mention this if they hadn’t reduced their decision to fewer than the 4 who made it to the final round, so I’ve taken it to mean they’re maybe deciding between me and one other. But now I’m worried they’re negotiating with that other person and I’m just being held as a backup in case that doesn’t work out. Thoughts?