If it's the only weapon they have, they will move away from you and not fire their damage pulse (or push pulse):

If they have other weapons on them, they do fire their damage pulse but they will still move out of range since their orbit range uses the largest range instead of the one on damage pulse.

Also the range seems to be inaccurate, it's not 50 but in this case it should be 10, the radius of the damage pulse.

How to reproduce:

1. spawn in a pulse only pirate:
   pulse test pirate.rar1 KBDownload
2. try to make it engage you if it does not do anything (bump it, shoot it with a low damage weapon)
3. notice that it flies away from you and does not fire its only weapon