Weird interpolation behaviour

[skuba31]

I was using metis class with COMPASS-U models and noticed weird time interpolation behaviour of equilibrium_map3d.

from cherab.compass.equilibrium.fiesta import fiesta_from_cudb
from cherab.compass.plasma.metis import metis_from_cudb


shot_number = 5400
shot_time = 1.5

equilibrium_shot = fiesta_from_cudb(shot_number)
equilibrium = equilibrium_shot.time_slice(shot_time)

metis = metis_from_cudb(shot_number)
metis.equilibrium = equilibrium

tep = metis.equilibrium_map3d('tep', shot_time, interpolate=True)
tep1498 = metis.equilibrium_map3d('tep', 1.498, interpolate=False)
tep1504 = metis.equilibrium_map3d('tep', 1.504, interpolate=False)