I'm not sure it's a bug, because the last time I dug into the intricacies of Unix terminal definitions was really long ago, and I ran away screaming. But it kind of presents a practical problem:

The cursor does not natively blink, and Emacs can't make it blink.

Also, the result of running tput cnorm and tput cvvis commands is identical, a rectangle cursor, when the first one is supposed to produce an underscore cursor, so something is very probably wrong.

This is kind of a problem in Emacs, because when background is used for highlighting (i.e. on TODO items in org-mode) the block cursor can become completely invisible while over the highlighted text, and blinking cursor becomes a necessity.