Sporadically

Does the error occur regularly or sporadically? Is the error reproducible?

I'm disabled and sporadically employed.

The language of instruction is mainly English. Sporadically, courses are also offered in the local language.

Valencia threatened sporadically in the first half with Miguel having a decent effort deflected wide by Ashley Cole, while Jordi Alba's near-post cross was flicked into the sidenetting by Pablo Hernandez.