For the location this issue is happening the business will not invest in the HSEC license.
It's a good article but not valid for us as we have to apply an input service-policy. Shaping is only possible with output policies. It is not possible for us the apply an output policy on the other side as it is ISP material.
It appears that you're using old IOS or an old platform, because in IOS-XE versions the CERM limit was changed to 250Mbps many years ago. The problem with CERM is that its measurement interval is very small, e.g. 1 sec or so. There can be microbursts and the 85Kbps limit is hit. Did you check show platform cerm-information?