Ah I see, I must have understood this incorrectly when I added this feature.
Please go to SuperTextMesh.cs, and on lik 1171, you should see some code that looks like this:
private static List<char> linebreakFriendlyChars = new List<char>(){' ', '\n', '\t', '-', '\u00AD', '\u200A', '\u200B', '。', '〜', '、', ',', '…', '‥', ' '};
If you remove '、' and ',' from the list like this...
private static List<char> linebreakFriendlyChars = new List<char>(){' ', '\n', '\t', '-', '\u00AD', '\u200A', '\u200B', '。', '〜', '…', '‥', ' '};
...I believe you should get the results you want. Please let me know if this works as you want, and I'll make sure this functionality is changed!