The Brief: A comma ellipses (,,,) is a more casual and dramatic version of the period ellipses.

DEEP DIVE
An ellipses is a set of three periods (…) and is used to signify when part of a quote has been omitted. Those three dots are actually named after the Greek word for omission, “ellipses.”
In the middle of a sentence or at the end, an ellipses also signifies a pause in speech or a sentence that trails off. In recent years, young people are using comma ellipses consisting of three commas in a row (,,,). Surprisingly enough, this isn’t a grammatical error.
Also, what's up with,,,,,comma ellipses,,,,,,?
— Gretchen McCulloch (@GretchenAMcC) November 28, 2017
According to Babbel and those who use triple commas, the comma ellipses signifies the tone of the message. It is a more casual and dramatic version of the period ellipses. It can even add a tinge of annoyance and frustration to the tone.
Comma ellipses can be spied on social media apps, especially those frequented by a younger user base.
People have also begun to substitute periods for commas in ellipses to give more of an unsure, uneasy tone. I’m guilty of doing it a lot whenever I’m nervous about something I’m saying; like asking “are you sure,,,,” or saying “ok,,,” when I think someone is angry
— neza✨ (@ritualgoth) March 4, 2018