There are two programs on the machine; O02020 Warm Up and O02021 Run In.
These programs are intended to run the spindle up to speed in a series of steps to purge out the oil that accummlates in the lower spindle bearing when the machine is not operating.
The Run In program should have been done when the machine was installed and checked out by the Haas technician and the Warm Up should be done every day if the machine gets cold overnight or if the machine has not been used for a couple of days.
Have you been using the machine or has it been sitting unused, how cold is your shop, have you been running the Warm Up program. It is possible to get a high spindle load when the machine is cold simply because it is stirring up oil in the bearings. It is also possible to overheat the spindle but this is less likely on a 6000rpm machine.