Horn and Sinew mastery not working

It seems this mastery either does not work, or the wording is not very intuitive. I just had a match, where research was completed and had around 180 kills with mangudai after that. Then opponents resigned (team game).
Does it have to be exactly 40 kills, not one more or less?

Hey @WiseConcil! There is a bug currently where completed Masteries occasionally won’t show as completed on the post-match screen. But if you go and check Masteries, it will show as completed. Are you sure it didn’t trigger and just didn’t show up post match?

Second thing to check is that you did indeed research the Improved version of the tech.

Let me know and I’ll have the team investigate if all is correct on your end. Thanks!

Thank you.

I am certain, I was researching the improved version:

Not sure, if this is helpful, but here is the match detail from AOE4WORLD:
(Maybe you can use the IDs from the URL)

I also researched Veteran Mangudai before doing the kills - can this be related?

I checked the mastery list as well, not just the post match screen (there indeed often missed some achievements, but that not big of a deal I believe).