The problem I asked in the latter half of ticket #3561 in the previous system has not been resolved.
In recent nesting suite I have 3 nests. The land sea mask is created fine when I have the smallest nest off Porto (u-cf930, u-cg028). However, the model suffers from the LSM problem when I set the smallest nest off SW England/Wales (u-cf597).
As shown here http://cms.ncas.ac.uk/ticket/3561#comment:13 the LSM has value 1 everywhere even though the nest includes areas over sea. Sometimes the nest is completely corrupted (also shown in the same ticket).
I initially had a problem in the large nest covering the North Atlantic that land-sea mask was wrong in the east of the prime meridian.
This problem has not been resolved but avoided by finding a domain that does not cause the problem. It looked like the problem happened when a region is set so that it extends to the Eastern Hemisphere only a little bit.
I feel like these problems may be related.
People suggest that I should do ANTS but it isn’t currently working. Also when I turn on ANTS LSM seems to be created before ANTS fails. So I think ANTS might not provide a solution.