Per Kea documentation:

When a data field is a string and that string contains the comma (,; U+002C) character, the comma must be escaped with two backslashes (\\,; U+005C). This double escape is required because both the routine splitting of CSV data into fields and JSON use the same escape character; a single escape (\,) would make the JSON invalid.

Accordingly, the pcode generated for time-zone should have the , double escaped.

For example, "CST6CDT,M3.2.0,M11.1.0" should be rendered as "CST6CDT\\,M3.2.0\\,M11.1.0".