Problem

When using a custom time range in Lite (and likely Dashboard), the chart X-axis labels show timestamps in the wrong timezone. Setting the picker to 8:00 AM - 12:00 PM local time shows data plotted at 9:00 PM - 2:00 AM on the X-axis.

Root Cause (under investigation)

The data flow involves multiple timezone conversions:

1. collection_time stored as DateTime.UtcNow (UTC) in DuckDB
2. Chart data points converted with .AddMinutes(UtcOffsetMinutes) (server's UTC offset from DATEDIFF(MINUTE, GETUTCDATE(), GETDATE()))
3. Picker dates converted via ServerTimeHelper.LocalToServerTime() (client local → server time)
4. X-axis range set using the converted server time values

Something in this chain is producing incorrect axis labels. The offset appears to be roughly double-applied or not applied at all to the axis range vs data points.

Environment

• Server UTC offset: -480 minutes (Pacific, UTC-8)
• Client timezone: Pacific (same as server)
• Picker set to: 08:00 - 12:00 on 2/15/2026
• Chart shows: 9:00 PM 2/14 - 2:00 AM 2/15

Affects

Both Lite and Dashboard (both use the same UtcOffsetMinutes + ServerTimeHelper pattern for chart time conversion).