issue with losing geometry shapes when loading sprites in 4.8p1 has been fixed in /EpicGames/UnrealEngine/commit/96fe5943a574f7c145f4ccc480770367da3b2d96 which will be part of 4.8p2. It only affected assets saved with exactly Paper2D version 13 (4.7.4-4.7.6 or main branch 4.8 prior to geometry refactor). I had tested with older assets saved in 4.7.0 which worked after refactor even without struct redirect due to an unrelated bug in SerializeTaggedProperties 
Cheers,