I got myself a workaround that seems to work for me.
Made a LISP (long live AI) that stores all layer and linetype combinations.
Sets everything to 'Continious', purges all linetypes, that reloads the linetypes and that restores the default settings.
This seems to do the trick to get rid off all 'corrupted' linetype definitions, and 'reloading' is replaced with a load function.