Below two queries. The second group on the former query is greedy, on the latter is not.

Why does the former work and the latter doesn't?

SELECT * FROM "table" WHERE "field" REGEXP '(Color|Material)=(\w.*)($|,)';
SELECT * FROM "table" WHERE "field" REGEXP '(Color|Material)=(\w.*?)($|,)';

I asked this question in Stack Overflow, I got no answers, but a comment says "The regex library used behind the scenes is broken".

Is the regex library used by DB4S really broken?