Member mentions showing the User ID instead of their display/nick name

[Mick666]

I assume this is a caching issue, but I've not been able to find any documentation about this.

I have my bot setup to welcome users, mentioning them as well as some channels:

As you can see, the first user showed up as their ID. The next user shows up as their name.

As far as I can guess, Discord shows the username for the most recent mentions, and stops trying to fetch the users details after the first few.

I figure Discord is falling back on the User's ID if it doesn't have the User's display name in its cache.

Related to this, any notifications from the server for these messages (on my ios discord app or windows desktop notifications) always show the ID. I would really like to have them display their name instead of their ID.

The code that creates this Embed looks like:

I cannot see anything in the documentation for the Member or the Embed to explain this. I can also see that other bots (like MEE6) don't seem to have this problem.

Is there something I'm missing? The only related discussion I could find, on Stackoverflow, said to use <@!{id}> instead of <@{id}>, which I've tried (didn't make a difference for the notifications).

[Rapptz]

The client only resolves mentions in embeds if the user is cached by the client. It's outside of the library's control and Discord doesn't really explicitly "support" it.