ETF Question

I'm trying to learn so bear with me if this is a dumb question...

I was comparing three ETFs and noticed one is a clear outlier as its NAV performance is considerably higher than its market performance...sometimes as large a gap as 12-14%.

Doing a bit of research, NAV is based on the value of the underlying portfolio on any given day...essentially, what the ETF should be worth. Market is the actual closing price of the ETF itself.

Am I an idiot or is a large NAV/Market gap be a good thing to pay attention to? Seems like that gap would imply that there's a ton of upward potential? Like AVUV, below, is a steal right now, eh?

AVUV -- YTD NAV 18.86% YTD Market 6.8%
AVUS -- YTD NAV 25.94% YTD Market 17.09%
VOO -- YTD NAV 28.04% YTD Market 28.05%