Assertion fails during the dotplot building

This bug is reproduced in debug mode only. There is no problem on release version.
1. Select

{Tools->Build dotplot...}

in the main menu.
2. Fill next fields of the "Build dotplot from the sequences" dialog and click the "OK" button:

{File with first sequence:}

_common_data/scenarios/dp_view/dpm1.fa

{File with second sequence:}

_common_data/scenarios/dp_view/dpm2.fa
3. Set newt fields of the "Dotplot" dilog and click the "OK" button:

{Minimum repeat length}

8bp

{Repeats identity}

80%
Expected state: dotplot appeared.
Bug state: assertion failed.