If you migrated over the same assets and they worked, plus the projects physics settings are the same, I’m not sure.
I would make a copy of your project before you try these but here are a couple other things to try.
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Create a new level and retest there (it’s possible the level has become corrupted)
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Create new assets for the platform and the box (they shouldn’t be corrupted because they worked in the new project but just in case it’s worth trying)
Just curious, have you migrated your project from past version of the engine? If so, what other versions has it gone through?