Frostmourne doesn't respawn reborn minions killed by weapon

Why would you even assume that?

A week ago a post was made where they told that the plan was to release a bug fix today:

As you see, the post does still exist … but it is no longer visible in the list of posts. Not sure if that’s because of a weird forum bug or a sign that they ran into more issues than expected and won’t make the planned release date for the fix.
But I think it’s safe to assume that they definitely ARE planning to fix this bug.