What were you trying to do that didn't work?

Using the timezone GMT shows a WARNING message in the /var/log/rhsm/rhsm.log:

2025-11-13 16:29:53,080 [WARNING] subscription-manager:3110:MainThread @connection.py:96 - Expected UTC timestamp, got '2025-11-13 16:29:52+00:00', drift check may be off.

What is the impact of this issue to you?

Seems to be just informational warning, and isn't causing any issues.

Please provide the package NVR for which the bug is seen:

The affected rpm is python3-subscription-manager-rhsm-1.29.47.1-1.el9_7.x86_64

The logging comes from this file /usr/lib64/python3.9/site-packages/rhsm/connection.py

How reproducible is this bug?:

Always

Steps to reproduce

1. Set timezone to UTC timedatctl set-timezone GMT
2. Refresh subscription-manager subscription-manager refresh
3. Observe the /var/log/rhsm/rhsm.log

Expected results

No WARNING message.

Actual results

Seeing a WARNING about possible drift in clock.

Additional notes

I added some logging to observe the tzname, and only when I use GMT, does the tzname show GMT. If I use WET or UTC, both in the same timezone as GMT, I don't see this behavior.

This is the log line I added to the get_time_drift method:

    log.info(f"REDHAT | Timestamp tzname: '{timestamp.tzinfo.tzname(timestamp)}'")

And it shows GMT when the drift check may be off message:

2025-11-13 16:28:33,029 [INFO] subscription-manager:3054:MainThread @connection.py:94 - REDHAT | Timestamp tzname: 'GMT'
2025-11-13 16:28:33,029 [WARNING] subscription-manager:3054:MainThread @connection.py:96 - Expected UTC timestamp, got '2025-11-13 16:28:32+00:00', drift check may be off.

If I use either WET* or UTC* which have the same time as GMT, I only see *tzname UTC (no drift check may be off warning):

2025-11-13 16:28:58,281 [INFO] subscription-manager:3073:MainThread @connection.py:94 - REDHAT | Timestamp tzname: 'UTC'