I had a look at the list of users a user invited. For example: https://meta.discourse.org/u/hawk/invited/redeemed.
On mobile, it looks like this:
Often, the usernames do not fit between the profile picture and the date. However, there is enough space on the right.
Then, I had a look at the desktop version:
Maybe the mobile version could look similar to that. I like the two columns with the headline explaining which date is shown.