If it cannot be reproduced in a project which is directly in OWB that suggests that OWB is working correctly and that there might be something in the data that comes from CA PPM.
If you look at the properties of the material resource
The first thing that strikes me is that there is no availability. Secondly the availability dates are blank.
Doesn't that mean that the resource is not allocated to the project?
Setting values for those
Does not make a difference and the value in Availability (1) does not stick.
The next thing is to look at the calendar.
Can't really say how the working days in the resource calendar are because of the Windows 10 theme.
However selecting a date and clicking Workday marks the right top corner with black to indicate override.
When I Autoschedule after that
.
No problem at all.
If you do not have the problem with the earlier versions could the reason be that either the material resource is not set up the same way or CA PPM sets up material resource differently by default in 15.1 (and may versions after that).