Getting back to this case because I encountered it again and completely forgot about this post. It would be nice if the "p4 help opened" usage mentioned that -x does NOT include exclusive files marked for *add*.
A colleague of mine found the following suitable workaround for command line usage:
p4 opened -a //mydepot/mybranch/... | findstr exclusive
That was exactly it. The account i was using only had 'read' access instead of open.
I was thinking the same thing about the message being returned by the reconcile operation, it would have been nice if the message was clearer.
(lol even a message calling me an 'idiot' for not checking permissions would have been tolerable )
Oh BTW I should point out that when i add the preview option '-n' in the command line, it outputs the message that the file is opened for edit. Leading us to believe that the command would have worked without the preview option.
BTW I was running some more tests and i seem to only have the issue with this particular depot.
I ran reconcile operations on other depots (streamed, non-stream) and the reconcile operation works fine through P4V and the command line.
The depot in question appears to have been created correctly:
# A Perforce Depot Specification.
# Depot: The name of the depot.
# Owner: The user who created this depot.
# Date: The date this specification was last modified.
# Description: A short description of the depot (optional).
# Type: Whether the depot is 'local', 'remote',
# 'stream', 'spec', 'archive', 'tangent',
# or 'unload'. Default is 'local'.
# Address: Connection address (remote depots only).
# Suffix: Suffix for all saved specs (spec depot only).
# StreamDepth: Depth for streams in this depot (stream depots only).
# Map: Path translation information (must have ... in it).
# SpecMap: For spec depot, which specs should be recorded (optional).
# Use 'p4 help depot' to see more about depot forms.
Date: 2017/11/27 14:26:39
Created by jwilson.