Decided to merge a bunch of these tickets into one, since they're more or less an identical issue.
Under certain circumstances while sneaking, the positioning of an item can be miscalculated, causing it to be offset from its intended position on a player. Known examples include:
Linked issues
duplicates 1
Attachments
Comments 2

All four affecting 1.13.2-pre1
Please leave merging tickets to mods.