It cannot definitely be due to the cap. Frequent causes are dried-up refills that have already been stored longer in specialist trade; Marathon refills do not necessarily last longer than standard refills. Start-up problems of this extent are very unusual, which is why individual factors like writing angle, imprint, paper as well as consistent closing after use are to be checked. A well-founded judgement is ultimately only possible if rollerball, refill and user are jointly assessed in a boutique. Until then, the rollerball should always be kept closed and not too strongly pressed.