Langmuir 3D w/ maxlevel=2 broken

[ax3l]

Inputs

Using the latest development of WarpX, I was trying MR with 3 levels (0, 1, 2) on the langmuir 3D test. Inputs files: inputs.zip

Textual output: output.zip

Plots

Everything works for amr.max_level = 0:

For 1 MR level with amr.max_level = 1 it still looks good, but has tiny artifacts:

For amr.max_level = 2 I see the following issues:

Plot Script

import yt

ds = yt.load('./diags/diag1000040/')

sl = yt.SlicePlot( ds, 1, 'Ex', origin='native' )
sl.set_zlim('Ex', -1.5e9, 1.5e9)
sl.set_log('Ex', log=False)
sl.annotate_grids()

[ax3l]

@WeiqunZhang since this is kind of a follow-up to #3777, does this reproducer help you to take a look at this?

The same test works well in 2D: #3979