It's barely a problem while making normal posts. That only happens when I create multiple posts, and then click "send" to post them all.
I his this while reporting spam. On loyce.club/badposts/spam.html, I click "report" with my middle mouse button (to open them in a new tab), then go through the tabs to report them.

So the problem is the post delay is also used as a Report delay. Merit doesn't have that delay, I can Merit 4 posts within the same second (and I've done that many times, but never reached 5).