Adding CLONE_SKIP to MyPackage results in abnormal thread termination. This is what i caught using eval:

OIO error: panic: del_backref at C:/Perl/site/lib/Object/InsideOut.pm 
+line 1305.
Package: main
File: C:\Development\workspace\ebi.ds.lite\_Scripts\bug.pl
Line: 27

Subsequent to the above, the following error also occurred:
    OIO error: panic: del_backref at C:/Perl/site/lib/Object/InsideOut
+.pm line 1883.
    Package: main
    File: C:\Development\workspace\ebi.ds.lite\_Scripts\bug.pl
    Line: 27


Trace begun at C:\Perl\site\lib\Object\InsideOut.pm line 1942
Object::InsideOut::DESTROY('MyPackage=SCALAR(0x1ba3b0c)') called at C:
+\Development\workspace\ebi.ds.lite\_Scripts\bug.pl line 27
eval {...} at C:\Development\workspace\ebi.ds.lite\_Scripts\bug.pl lin
+e 27
main::th at C:\Development\workspace\ebi.ds.lite\_Scripts\bug.pl line 
+22
eval {...} at C:\Development\workspace\ebi.ds.lite\_Scripts\bug.pl lin
+e 22
Unbalanced string table refcount: (1) for "1" during global destructio
+n.
Scalars leaked: 1
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This class have to be implemented via OIO and i can't fallback on classic hashref based object.