I am so glad I found this post. I ran into this issue only today and it was driving me crazy. I noticed this post was from Dec. 2017 and it is now March 2018 and I am having the same problem so It has apparently not been fixed by Webroot.
I contacted Webroot support to find the best possible workaround.
I will say that allowing Chrome in their identity protection setting only partially fixed the issue for me. So I think Webroot is doing more scanning of other apps and it's still causing problems with Task Manager. I haven't had time yet to test things further unfortunately.
I am quite disappointed because I just recently switched our company to Webroot from something else that I was having a lot of issues with.
Our IT dept uninstalled Webroot and installed a different anti-virus. This fixed it.