Environment

• DNN: 9.13.9
• 2sxc: 19.3.5
• Connect.Koi: bundled with 2sxc 19.3.5
• Theme: Custom Bootstrap 5 theme (“Base”), no koi.json
• Connect.Koi not actively used

Problem Description

On every Default skin request (/Default.aspx), DNN EventLog records an exception:

Connect.Koi: Error while loading framework settings from koi.json

Inner exception:
The UTC time represented when the offset is applied must be between year 0 and 10,000.
Parameter name: offset

StackTrace:
System.Runtime.Caching.HostFileChangeMonitor
Connect.Koi.Dnn.DetectKoiOfCurrentDnnTheme.AutoDetect()

Context values are always:

PortalId = -1
TabId = -1
UserId = -1

This indicates the error happens very early in the request pipeline, before a portal or tab context is available.

Root Cause Analysis

DetectKoiOfCurrentDnnTheme.AutoDetect() always tries to attach a HostFileChangeMonitor to the resolved koi.json path:

policy.ChangeMonitors.Add(
    new HostFileChangeMonitor(new[] { koiPath })
);

When and what happens?

• the default skin does not contain koi.json
• skin metadata is resolved from cached values
• the resolved path is invalid or points to a non-existent file
  In this situation, .NET internally attempts to construct a DateTimeOffset from invalid file metadata (LastWriteTimeUtc), which throws:

The UTC time represented when the offset is applied must be between year 0 and 10,000

The exception is then logged as:

Connect.Koi: Error while loading framework settings from koi.json