ABAP Short Dump on append of a sorted tableITAB

The program short dumps when appending a sorted table in the wrong sort order

data: sorted_tab type sorted table of ty_tab with non-unique key key, line type ty_tab. line-key = 1. append line to sorted_tab. "works fine" line-key = 2. append line to sorted_tab. "works fine" line-key = 1. append line to sorted_tab. "<==== Short dump here"

Use INSERT in stead:

data: sorted_tab type sorted table of ty_tab with non-unique key key, line type ty_tab. line-key = 1. insert line into table sorted_tab. "works fine" line-key = 2. insert line into table sorted_tab. "works fine" line-key = 1. insert line into table sorted_tab. "works fine"