Official comment
Increase the buffer again; your computer specs or other applications running in the background on the computer could certainly contribute to system resource usage requiring a higher audio buffer size, meaning the computer can't keep up in providing a consistent stream of data for the audio output.
The idea is you set it to the lowest possible value where no audio errors persist when running as much as you could possibly use during a mix session (eg. effects, samples, etc). This value varies from computer to computer, so even two identical computers brand-new out of the box may require different buffer sizes.