After upgrading from app-editors/vim-8.0.0386-r1 to app-editors/vim-8.0.0938 I noticed that the moment I start vim, the cursors starts blinking and stays blinking even outside of vim, regardless of settings of the terminal or the vim itself. It does not happen however if I start them vim in xterm. After dowgrade to app-editors/vim-8.0.0386-r1 the issue is no more.
The commit that broke the cursor: commit 3cd43ccccb03b2e68df9c8a344a87e51c007c656 (HEAD, tag: v8.0.0918) Author: Bram Moolenaar <Bram@vim.org> Date: 2017-08-12 19:51:41 +0200 patch 8.0.0918: cannot get terminal window cursor shape or attributes Problem: Cannot get terminal window cursor shape or attributes. Solution: Support cursor shape, attributes and color. I will poke upstream.
It seems like it was fixed upstream, https://github.com/vim/vim/issues/1986#issuecomment-323794546
Should be fixed in 8.0.0983 now in the tree.
Can confirm that it is fixed for me.