citizens npc with model engine trait loses model after server restarts

Citizens 2.0.30 #24 (latest)
ProtocoLib latest dev
meg 3.1.4 
paper 1.19.3 latest

how to reproduce

1. make npc
2. /trait add meg_model
3. /meg npc model npc_id add meg_id
4. check model is properly applied to npc
5. /npc2 save ( save it to file )
6. restart server
7. model is not applied in npc

how to fix temporarily

1. /npc select
2. /npc2 type current_npc_type , slime for me 
3. check model is reapplied agin

few notes

data is properly written into citizens caves.yml
just doesn't reapply after server restarts