Maybe, but this can go on for weeks, typical of bubbles
You wouldn't know it by the last couple of days, Friday in particular, but the past few months have been dominated by late-day selling pressure.
The Cumulative Last Hour indicator looks at the last hour of trading in the S&P 500 fund, SPY. If the fund rises during that hour, then the indicator adds 1 to the running total. If it drops, then it subtracts 1.
Recent months have seen a continual erosion in the indicator, to the point where it's at the lowest level in 6 years. When stocks have been persistent hitting new highs while the Last Hour indicator was plumbing new lows, it has been a warning sign.
What may be especially notable about the current behavior is just how persistent the selling has been during the last hour. Over the past 3 months, the indicator has dropped 5%, which doesn't sound like a lot, but it's the biggest drop in 25 years.