Hi @alxpck, sorry for the delayed response here!
This is actually coming from the core ‘user directory’ behaviour - you can see it if you open /u here on Meta and try filtering by username. The current user will always be shown in the list, regardless of what you filter by. For example
But you’re right that it becomes super confusing when filtering by groups. If someone is deliberately filtering like that, they probably don’t want to see themselves (unless they match the filter).
I opened a PR in core here for discussion: https://github.com/discourse/discourse/pull/11310
Let’s see how that goes - if we decide not to make that change in core, we can look at a workaround for this theme component.