Attaching / Detaching a blueprint actor to a player in a network environment causes location errors when the detach occurs. Even without the attach events being replicated or the blueprint's movement being replicated (replicating movement stops this from occurring), the cube is moved on the client. When the detach occurs, the cube resets to 0,0,0 instead of staying at its location or even resetting to its original location.

Another odd thing, although this may just be a symptom of doing networking tests in PIE, if you eject (F8) on Player 1 (the server), the cube also goes to 0,0,0. Whether you eject or not, after the detach, the blueprint also shows as being at 0,0,0 in the World Outliner, although it is not on the Server if an eject hasn't occurred.

Link to project: [Link Removed]

Regression?: No
This also occurred in 4.13/4.14

Steps to Reproduce
  1. Download the attached project (Link in description)
  2. Ensure that the number of players is set to 2 for the PIE settings
  3. Press play
  4. Click in the viewport
  5. Aim at the cube in front of Player 1 and left click on it, this will cause it to attach to the player
  6. Move the cube around by turning the camera horizontally, noticing that while the locations of this cube that are being printed are not equal between server and client but both are updating.
  7. After 10 seconds, the cube will become detached.
    Result: The cube goes to 0,0,0 for the client but stays in place for the server
    Expected: The cube stays where it was when the detach occurred

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ComponentUE - Networking
Affects Versions4.
Target Fix4.22
Fix Commit4495485
Main Commit4804559
Release Commit4862694
CreatedApr 24, 2017
ResolvedOct 22, 2018
UpdatedFeb 12, 2019