SAFE_POINT if select "Copy (custom format)" action on aligment with gaps

Issue is reproducible on 39.0/40.0 versions
Scenario:

1. Select align_subalign.aln, see attachment
2. Select from context menu Export/Save subaligment
3. In dialog "Save selection as subaligment" select Column from 16 to 24 where only gaps were present
4. Exported file align_subalign_subalign.aln appears in the project
5. Select s1 and s2 sequences
6. Select from context menu Copy/Paste->Copy(custom format)
   SAFE_POINT triggered

   Invalid crop column range: 1..9
   Trying to recover from error: Invalid crop column range: 1..9 at D:\ugene\ugene\src\corelibs\U2Core\src\gobjects\MultipleSequenceAlignmentObject.cpp:131
   Assertion failed: 0, file D:\ugene\ugene\src\corelibs\U2Core\src\gobjects\MultipleSequenceAlignmentObject.cpp, line 131