The phrase "again unknown" is correct and usable in written English.
It can be used to indicate that something has become unknown once more after being known previously.
Example: "After the data was lost during the system crash, the results are again unknown."
Alternatives: "once more unknown" or "unknown again".
Family paths cross and sever, then cross again: unknown to each other, both Tomas and Teige venture into the American West, "landless and adrift in the anonymous vastness".
Security experts found that the attacker — which was again unknown — was hijacking internet traffic to send visitors to websites that contained scripts from Chinese search engine Baidu to the two pages.
where ω j n and θ k n are again unknown smooth functions defined on an interval [ 0, T n ], T n ≤ T. Evidently, the boundary conditions v n ( 0, t ) = v n ( 1, t ) = ω n ( 0, t ) = ω n ( 1, t ) = ∂ θ n ∂ x ( 0, t ) = ∂ θ n ∂ x ( 1, t ) = 0 (64).
A further advanced pregnancy was reported in September 1582 by the French ambassador, yet the outcome is again unknown.
The reasons for these recent changes in incidence are again unknown.
TNAP is an enzymatic generator of inorganic phosphate and an established essential promoter of tissue mineralization, but it is again unknown how diminished TNAP activity leads to craniosynostosis [ 41, 58].
Whether Mrs. Clinton is weighing in again is unknown.
Brokers said the reasons for his selling again were unknown at this point.
And sometimes people develop food allergies as adults, again for unknown reasons.
And many of them, again an unknown number, still lie under rubble, rotting in the heat.
According to a data recorder analyzed later, its power waned, surged and waned again, for unknown reasons.
