unable to simplify to a complex interval approximation

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Dear all,

Once simplified, here is the problem. This is something that goes smoothly with Sage 8.6 and not with Sage 8.1. It turns out that Sage 8.1 is the one bundled with Ubuntu 18.04 LTS so I'm interested in solving this issue. I'm also interested in this question in itself. Here it is:

C = ComplexIntervalField(200)

C(-psi(1/3))

That work's just fine in Sage 8.6 but Sage 8.1 answers:

TypeError: unable to simplify to a complex interval approximation

Of course C(psi(1/3)) works just fine. Many thanks in advance