More clarification on what you mean by “dead spots” and “glitching” would be helpful. This is my guess based on what you said:
I’m guessing that your octaver pedal is a digital pedal. It uses computer code to calculate octaves from the original sound that it receives. What might be happening when you hit your “dead spots” is that the processor on your digital pedal freaks out and “glitches” because it doesn’t know how to translate the dead spot to an actual note.
Analog pedals use really simple components and very minimal computer code if at all. I suspect a true analog chorus pedal probably won’t “glitch”. A digital chorus pedal mimicking analog might though.
Again, more clarification on what you mean would help us figure out what’s going on.
What you describe as "glitching" could just be resonant frequencies playing with the signal. There are certain notes I hit when I have a few fuzz pedals going that make it go from wild an unwieldy to very subdued and muted. Could be a similar thing.