A Cyclone Phrase™ is one in which

for each word, the letters in the first half of the word (including the middle letter, if there is one) are in alphabetical order, and the letters in the second half of the word (again including the middle) are in reverse alphabetical order.
The one exception is "an old bum begged". The word 'old' does not have this property: the first half, 'ol', is not in alphabetical order.

A Cyclone Phrase™ is one in which

for each word, the letters in the first half of the word (including the middle letter, if there is one) are in alphabetical order, and the letters in the second half of the word (again including the middle) are in reverse alphabetical order.
Example:\begin{array}{|l|l|l|}\hline\text{Word}&\text{First half}&\text{Second half}\\\hline \text{all}&\text{al}&\text{ll}\\\text{alone}&\text{alo}&\text{one}\\\text{at}&\text{a}&\text{t}\\\text{noon}&\text{no}&\text{on}\\\hline\end{array}The one exception is "an old bum begged". The word 'old' does not have this property: the first half, 'ol', is not in alphabetical order.

A Cyclone Phrase™ is one in which

each word can be separated into two pieces, the first with letters in alphabetical order, the second with letters in reverse alphabetical order.
Examples:
all alo-ne at noo-n
blu-rb in my blo-g
deerw-eed an-d alo-e
chi-c dimp-le
it is adjou-rned

The problem is, every phrase listed as a Cyclone Phrase™ satisfies this rule. There is no error. Presumably that means this is incorrect.

A Cyclone Phrase™ is one in which

for each word, the letters in the first half of the word (including the middle letter, if there is one) are in alphabetical order, and the letters in the second half of the word (again including the middle) are in reverse alphabetical order.
The one exception is "an old bum begged". The word 'old' does not have this property: the first half, 'ol', is not in alphabetical order.