There is a SERIOUS bug with the challenge system

I have this Challenge which needs 25 kills in a Slayer match.
I have 13 kills by my hand but only got 2 progression. This is a very serious bug that needs to be fixed asap.

For reporting bugs or issues, we recommend heading over to https://aka.ms/HaloSupport for further assistance. Please review the latest known issues and submit a ticket if your issue is not listed.

Thanks!