I don't think the fact that developers are surprised by speedrun times means that a game is necessarily bad! (And even many of the most extraordinarily beloved games have glitches, often because realistic physics simulation is hard.)
I think I saw a video of Bennett Foddy in which he noted that other people could complete "Getting Over It with Bennett Foddy" considerably faster than he could, and maybe faster than he imagined anyone would be able to.
In good software, the bugs don't cause user-facing issues. QA teams aim to make software good by finding them.
Speedrunners aren't users or QA. Speedrunners find bugs no matter what. From the developer's perspective it really doesn't matter if you can save 20 hours beating a game by clipping through the wall next to the boss, if that clip is so immensely complicated to perform that no user would ever encounter it naturally. The devs can be surprised, or not surprised, to hear their game was beaten much faster than they anticipated by speedrunners; either way it does not make their game worse or rushed or a product of bad communication.
The Legend of Zelda: The Wind Waker came out in 2002 and sold 4.6 million copies. In July of this year, a new bug was discovered by dedicated minds, not randomly but after nearly two decades of hard work, that saved two hours on the speedrun by clipping through a barrier that was supposed to be unpassable. Does it really matter from a quality standpoint if this bug exists or not? Would your original rating of The Legend of Zelda: The Wind Waker be lessened 17 years later because this bug was found by people who perhaps spent more hours trying to find it than you've spent playing video games in your entire life?
A: That is true for all games
or
B: You're holding everybody to too high a standard.
Some recent examples: There's a glitch in Zelda: Breath of the Wild where if you shield surf onto an enemy while it's taking damage while you're in slow-mo because of shooting an arrow while falling, you'll bounce off of them about a mile into the sky. In DOOM (2016), there's a physics bug that lets you rocket into the sky by standing on a railing and then... standing up. You can also glitch through doors by triggering a specific take-down animation on zombies.
Those are incredible games, and relatively bug-free.
The game can be a 30 hour game if you hussle or as far as 200 if you don't.
First of all the fact that the game could be finished in 12 minutes was a surprise to both devs.
And at several points during the video dev#1 expressed surprise over a shortcut the player was taking, while dev#2 said he did that in testing all the time.
Seems like a lack of both QA and communication.
Projects are often rushed to completion for shipping, and open world games can't be the easiest thing to test. You're balancing player freedom and bug hunting. It's a challenge I can only imagine.