Is this normal?

[2cuteboys]

Is it attention seeking? Like she does it and then looks at you or the other kids for a reaction?

Talk to her parents about it and also reflect on what's going on when she does it at your house - try to find out when she does it (like when she's overwhelmed, or when you/they are busy, tending to other children), and what is done. If everything is dropped and she gets instant attention and cuddles after, of course she'd keep doing it. I've only ever seen it as a way to get attention, but its possible its something else.

Even if its behavior seeking, you of course need to ensure her safety, so you can't ignore her while its happening, but you can give her as little attention as possible while you deal with it. Have a pillow handy and stick it between her and the wall, or gently move her to the middle of the floor when she starts (if its a wall she generally bangs on), and don't give her any attention - no eye contact, no speaking to her, don't even check for a bump until she's calmed down at least a little bit. When she starts to calm down tell her quietly and without eye contact that you will talk about it when she is quiet/stops banging. When she's calm give her a lot of attention and praise her for calming down.
Give her a replacement behavior and touch on it during the day (when she's calm, not upset). Just remind her "if you want me, you can tap my leg/call my name" and really reward her when she does the replacement.