Did you disable the URL-Filter-bot-petal-string1 rule before adding this
rule. If not, it's obvious why this rule did not trigger. Otherwise,
it's not yet so obvious.
It's obvious why this rule did not trigger. You do not quite yet
understand what Offset = URL means. The URL does not contain the string
PetalBot. This is the same error you made with your MJ12bot rule.