plot : ValueError: Unrecognized character l in format string

[AXE4fnrYIY]

plot is behaving funny when used with DG 0 functions. In 1D it throws

ValueError: Unrecognized character l in format string

when called with a DG0 function and the label option. This doesn't happen with DG1 functions. It also doesn't happens in 2D (although python spits out another warning).

MWE (dolfin 2018.1.0, which I can't select from the dropdown menu...)

from dolfin import *

# mesh = UnitSquareMesh(10, 10)
mesh = UnitIntervalMesh(10)

DG0 = FunctionSpace(mesh, "DG", 0)
DG1 = FunctionSpace(mesh, "DG", 1)

u0 = Function(DG0)
u1 = Function(DG1)

plot(u0, label="0")
plot(u1, label="1")