one's strength can become one's weakness
Proverb warning that over-reliance on a strong point may turn it into a vulnerability.
「長所は短所」というから、自信があるところこそ気をつけなさい。
As the saying goes, 'Your strength can be your weakness,' so be especially careful where you feel most confident.
A set phrase composed of 長所 (strong point) + は (topic marker) + 短所 (weak point), literally 'a strong point is a weak point'.