Boolean difference solids generates thin walls?

 From:  Frenchy Pilou (PILOU) 23 Nov 2019  (4 of 8) 
9592.4 In reply to 9592.3 
Your object seems perfect! :)
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So seems your Print programs don't know how to fill the internal part...have you try to scale your original?

EDITED: 23 Nov 2019 by PILOU