The problem obviously stems from the fact that these applications only use a premium microphone on the headphones, which should only be used to reset the noise. Obviously, this problem has also been revealed on older models including OnePlus 5. OnePlus 5T and OnePlus 3. This does not affect all applications; Instagram, for example, does not seem to have this audio problem when playing a sound recorded on OnePlus's phone.
Some users of OnePlus 6 and OnePlus 6T wonder whether the problem with the microphone is why they have trouble activating the Google Assistant when they appear: "Hey Google." Fixing this issue may require nothing more than software updates, though third-party applications are included.