"Age" field is in some cases (?) a huge rational number

[Vaguery]

I'm running an instance of clojush.problems.integer-regression.the-idea-of-numbers and I'm pretty sure I never wrote any code in the problem spec deciding on "age". However, in the STDOUT spew, I see

Age: 416886365146724193428680855522749813242630129137636354462951844668759613896387554235618397140033714500623399285533350249757088484163060901339588402071867348915901644121125336047661747845058135524768843625503043539936419225234545523839705884441381503605958701767604027334978821529751807045994108071089261225935236185677441877101259373211825602560532884133183405382546668134913378217677597913907094247648001311953597335672308780336854774741720695612740266202268285180747297397645329973537/177849665908376178480067256262069457263276938048551357277672892375014732279076608955939130304695877669943814084564197534980428225821135917265540066806451240478250340314481663906922822793380348156143723045100335309061622384261672694610740143155592455966508169316987401256119508646489949647511118315568388118761846128007661245467449875768595568823991535313062885161184880996810698962679258823274259060039841201558567373287744033665895100578047716987152986238155883829184642505458581504

But I have not seen that in other problems? Is it because of something.... integer-y?