Thanks a lot, Joachim
I confirm that the fix in the nightly update solved my problem. Unfortunately, I immediately encountered another (cf. bug report [1]), so I decided to give HDG a go, although I have not used it before.
Since I am interested in nonlinear problems, I wanted to adapt the HDG example from Tutorial 2.8 to use a Newton solver (the same one I used earlier). However, when I go about this the usual way, the Newton solver complains that my "a" matrix is singular (cf. minimal not-working example [2]). It is not clear to me why this is the case, as I have not modified "a" apart from the addition of the load term. Any guidance would be much appreciated!
(Note that I am here trying to solve the same linear problem as in Tutorial 2.8, just using a Newton solver instead of the matrix inversions used in the tutorial.)
[1]
github.com/NGSolve/ngsolve/issues/63
[2]
gist.github.com/blakseth/91da94676215c17e9ded3ed125e1b3f9
Best,
Sindre