The company's shares hit their lowest since the week of its IPO last year and are down approximately 50 percent for the year and 44 percent in the last three months.
Wall Street analysts from Stifel, Oppenheimer and Dougherty called the HERO4 Session price cut less than three months after the July launch unprecedented in GoPro's history when contacted by CNBC Pro.
A price cut means "the product is likely not selling as much as expected," said FBN Securities Shebly Seyrafi in an email.
Investors are also disappointed GoPro didn't revamp the high end of their lineup for the 2015 holiday season.
"The announcement of the full 2015 camera lineup without a follow-up to the HERO4 Black and Silver will likely come as a disappointment to those expecting a marquee product release ahead of holiday," wrote Stifel's Jim Duffy in a note to clients Monday morning.