[Bug] CFPropertyListCreateFromXMLData parser error when USER environment variable is set

Re-opening #57192 (auto-closed as stale, not fixed). Still reproducible on 2.1.286 and 2.1.287.

New finding: the warning is triggered by the USER environment variable. Bisecting the environment showed:

• env -i HOME=$HOME PATH=$PATH TERM=xterm-256color claude → no warning
• env -i HOME=$HOME PATH=$PATH TERM=xterm-256color USER=$USER claude → warning appears

Bug Description
On every interactive start of claude, the following message is printed several times to the terminal:

claude[PID:TID] CFPropertyListCreateFromXMLData(): Old-style plist parser: missing semicolon in dictionary on line 3. Parsing will be abandoned. Break on _CFPropertyListMissingSemicolon to debug.

Claude Code keeps working normally afterwards; it is a cosmetic issue.

Reproduction

• Happens right after startup (after the folder trust prompt), in iTerm2 and in a plain pseudo-terminal.
• All plist files in ~/Library/Preferences pass plutil -lint.
• Does not occur with claude -p.

Environment Info

• macOS: 15.8 (x86_64)
• Platform: darwin (Darwin 24.6.0)
• Terminal: iTerm.app
• Version: 2.1.286 and 2.1.287 (both affected)
• Feedback ID: 741f3d30-32ba-4d3d-8bd1-03c01f13c9c3