I had a similar issue with my desk phone being 4 hours off, but my Grandstream phone is connected to a 3CX IPPBX. My problem was a configuration issue in a profile. In your case, double check settings in your Global Profiles, model templates and individual phone templates. As you make settings in each, from Global to individual phones, behavior can change, and not always for the better. Generally, it's best to set time config in the Global profile and avoid changing it at the model and extension level. This keeps every extension and device on the same time schedule.


Sometimes the thoughts in my head get so bored, they go for a stroll through my mouth. This is rarely a good thing.