Errors are thrown when using Additional Editor Instances with Manual mode

Steps to reproduce:
1. Open the attached project “IN-130894”
2. Observe the Console window

Actual result: Errors are shows up the Console window
Expected result: The Player 2 Game view opens, and no errors are shown in the Console window

Reproducible with: 2.0.0-pre.1 (6000.3.0a6, 6000.3.10f1, 6000.4.0a1), 2.0.1 (6000.3.10f1, 6000.4.0b11, 6000.5.0a5)
Not reproducible with: 1.6.3 (6000.0.69f1), 2.0.1 (6000.5.0a6, 6000.5.0a8)

Reproducible on: Tahoe 26.3 (25D125), Windows 11
Not reproducible on: No other environment tested

Notes:

• The Player2 Game view window might open, but it’s not consistent
• Between changes of the project version, I advise deleting the library folder
• Errors shown after opening Player 2
  “You may not pass in objects that are already persistent”
  “[Worker1] AssertionException: Assertion failure. Value was Null”
• If the errors aren't reproducing you can try launching one of the additional clients through multiplayer status menu