Issues recognizing GAFF2 atom type

[eventfulsean]

Hi,

I generated topology for a small mol using ACPYPE and trying to merge gaff2.dat with the .frcmod via 'processAmberForceField.py' but I'm getting the following error:

...
element_symbol = md.formats.mol2.gaff_elements[atype]
KeyError: 'ns'

Generating using ACPYPE a gaff type topology and merging it to gaff.dat works perfectly. The way I see it, 'ns' is a valid GAFF2 atom type so am not sure what's going on. I'm using gaff2.dat distributed in AmberTool18.

Thanks in advance.