I made a local new clean install of WordPress and Toolset plugins, everything on latest version.
As soon as Toolset Forms is activated, the issue appears.
Please also note that I have another site with Toolset Forms activated and the issue does not appear.
During troubleshooting, I was able to reproduce this issue on my test website as well.
One of the hidden post types from the Toolset Forms plugin is incorrectly shown at the bottom of "Access Control" section, under the title "Posts".
Appreciate your report and I have forwarded these details to the concerned team. I will update you through this ticket, as soon as this gets resolved.
For now, you can continue using the Access plugin and this repeated "Post" entry shouldn't affect the access control settings for the actual post type "Posts".
(please use the settings under the first "Posts" item and not this second one)