I had something similar and reported it in FT.
https://www.reallusion.com/FeedBackTracker/Issue/Artifacts-when-rendering-hair-close-up
Molly (RL) provided a solution:
Please download ROV Tool, double-click IC7-CC3-Rov-ON-2.reg and try it again.
Please let me know the result.Thank you very much.
Molly
Reallusion