Marked for Death Annoint not working on Merc

I have assassin's mark on my character and marked for death annointed on my mercenary. I have necessary curse limits too so the mark isn't getting overwritten. Based on the wording of marked for death this interaction should work as it doesn't say that culling strike only works on marks 'you' inflicted. I believe this is a bugged interaction as the mercenary should be culling.

I am replicating the same exact issue.

Was excited to anoint marked for death with an expensive tainted oil for my merc. Doesn't work :(

+1 on this

For me, it works with the default "Culling Strike" wording, but not with "Culling Strike against Marked Enemy."