'it is sometimes unclear' is a perfectly correct and usable statement in written English.
It is often used to indicate uncertainty about something. For example, "It is sometimes unclear how we should proceed with this project."
Yet it is sometimes unclear, from the city's own financial reports, exactly how much it is spending on technology.
The movie's flaw is that it is sometimes unclear if it really is about The Shining – or merely about cracked and delusional interpreters.
It is sometimes unclear whether a particular incident report is based on firsthand observation, on the account of an intelligence source regarded as reliable, on less trustworthy sources or on speculation by the writer.
As the country's new leader, President Thein Sein, who was inaugurated in March, pushes through a raft of new laws, it is sometimes unclear whether new or old laws apply.
Yet it is sometimes unclear when the line between free speech and harassment has been crossed, and that makes some women hesitant to come forward, said Ms. Kittappa, who now volunteers for Hollaback.
In poetry, it is sometimes unclear whether the voice is the poet's or not, and the reader's not knowing can add to the poem's obscurity; in fiction, the writer, having more words to play with, more often creates fictional realities which the reader knows to be entirely separate from the author of the book.
It was sometimes unclear, as the evening wore on, which group he belonged to.
In 1996, Thomas Friedman, the New York Times columnist, remarked on "The NewsHour With Jim Lehrer" that there were two superpowers in the world — the United States and Moody's bond-rating service — and it was sometimes unclear which was more powerful.
Separate series were created for the Guardian and Observer adverts and within these the adverts were arranged broadly chronologically, although it was sometimes unclear whether the date referred to the production or broadcast of the advert or a later compilation.
In California, the position is mostly seen as a relic of a time when, if the governor travelled out of state, it was important to have a backup in Sacramento to do business for him; now that governors can easily take care of state business even while travelling, it's sometimes unclear what, exactly, the lieutenant governor is supposed to do.
