I assume you are on graphene os. If so install the florisboard alpha version of keyboard from their github and it fixes the amethyst crashing issue. It is discussed on amethysts github.  

 CalyxOS with Open board. I hated Florisboard for some reason, but will try again. Thanks! 

 Yes thr board sucks but use it only when you have to tag someone, rest of the time used your preferred option.