Flow past cylinder - Lift coefficient

[lauguimel]

Dear Fppimenta
I am interested in calculating the lift coefficient of a cylinder in a channel with a viscoelastic flow, depending on its y-position. I made some computations and got some results and to explain the results obtained, I then checked the Newtonian case for Re=0 (ok, I should have done this in first place !).
Unexpectedly, the lift coefficient for the Newtonian case doesn't remain null when moving the cylinder in the y direction. Even if at the center it is null ($\approx=10^{-14}$), it goes up to $\approx=10^{-4}$, in the upper half part of the channel which is very similar to the results of the elastic case. Based on literature, this lift coefficient should remain null for a Stokes flow wherever the position in the y-axis.
I have doubled checked that the convective term is disabled in fvSchemes, tried multiple convergence test (in time, mesh, etc) and I am not able to figure out what is wrong.

Have you an idea ?
If you want to have a look, I set up a minimum working example here based on your tutorial:
https://cloud.univ-grenoble-alpes.fr/index.php/s/drbj62AKBwZMNBx

Thanks a lot in advance for any suggestion you may have !
Guillaume