We have a cloud instance with the same issue on the G/L Register.
We looked at their code an inside the Type Helper Codeunit, they are have a method called GetUserTimezoneOffset which uses a DotNet TimeZoneInfo;
This is the culprit.
For us, while we are in daylight savings, it should return -7 but it returns -8.
One of our users noticed it on this report but other may be coded differently.