I know the obvious thing to think is to make the healing station more passive, so you can not use it in the middle of combat. But I would be careful with that.
Aura is probably the merc I have played with least so far, because I don’t find her particularly interesting. Remove her “combat station drop” and I see absolutely nothing appealing about her any more.
On the other hand, I actually really enjoy playing against her. Taking out the station rapidly is a nice challenge (and it requires quick thinking when the best option is to sacrifice one’s life to take out the station). Sometimes it’s impossible to do it fast enough, but then I know the position exactly and it won’t happen again. Unless the Aura keeps moving the station around smartly, which also requires some skill. In any case I simply haven’t seen or encountered a situation yet in which Aura consistently locked down a part of the map. It always seems to be a short term measure, that only lasts until the other team wisens up to it, so I don’t think the design is inherently flawed.
The most frustrating situation for me is probably when I am in a duel with Aura and she plops down a station just in time to heal her back up to full health. But this manoeuvre doesn’t work often, and it’s still possible to take the Aura out with flawless aim.
All of this adds interesting dynamics to the game. If you nerf the station to not be effective during combat any more, then you take away all of these dynamics and Aura simply remains as a fast moving flyweight that can revive and support from the backlines.
I think the current design fits the fast paced and aggressive design of the game very well, so if changes are needed, I would be in favour of small stat tweaks (like the recent health reduction to the station), rather than a radical redesign of how the station works.
I understand that this may well be a minority viewpoint, so just take this as another perspective on it.