You can go to the ADE (https://cloud.aldebaran-robotics.com/) and set a manual update to 2.8.6 :
You will then need to downgrade your NAO through the webpage.
Unfortunately, I did not get a chance to try this out last summer, and the robot where this was happening is currently at another location. I'll be collecting the robot in late June and will try it out then.
I will say that I tried this with a different NAO 6 and I could not reproduce the issue. So, I haven't had a chance to follow this up more.
Did it worked?
It's a known issue that is still under investigation, but one of the possible lead could be that it is linked to the sensors of the hand that may detect contact when there is none. This is due to a hardware limitation of the product that is not corrected yet.
However, have you tried going back to 2.8.6 (I assume you were using this version of NAOqi before 2.8.7 ?) to see if it is working again ?