MUX Timesheet total availability does not take into account resource calendar, or any other calendar but the Standard. The total number of hours (hrs) for you do not match your personal / assigned Calendar
STEPS TO REPRODUCE:
Expected Results: MUX Timesheets should show specific resource availability in timesheets
Actual Results: MUX Timesheets will only show Standard Calendar in My Timesheet/ Review and Approve pages
Release : 15.9.3, 16.0
Component : CLARITY TIME MANAGEMENT
This is tracked under DE62594. The change is due to the fix for defect DE60880 MUX Timesheet Availability does not match Classic (Days). The application is not designed to use the Resource Calendar in the Modern UX at the moment. It might have worked in an earlier version due to the use of some common components. However, this was not the expected behavior. This information is based on Development's review.
Behavior has been updated in 16.0.1 and patched in 15.9.3.2 and 16.0.0.1
Also see how to make sure timesheet totals are updated, if you just modify the Resource Calendar: MUX Timesheet Hours do not reflect the Resource Availability