This submission was a user's mistake, see GFN-15 MEGA thread.
As far as I understand, T5K allow you to submit any non-duplicated prime even if it's small because this prime can, for example, be a member of the chain. For example, we submitted few tiny GFN-13 primes because they formed a Cunningham chain, big enough to enter top 20 in this category.
An erroneously submitted prime should be automatically deleted after some (unknown to me) time. Hoping that submitter would not get a ban or other penalties from T5K.