Geth incursions mission PS5

So currently trying to complete a mission in Mass effect 1 named UNC: Geth Incursions. After completing the 4th outpost, one of my Ai companions says I have one more left. So I figured it was Maji planet in the Vamshi system because I didn’t hear the SFX of completing a mission. I searched through the internet to see what I’ve missed and found out I had to kill a geth colossus after killing the set of Geth Rocket troopers and snipers. However since it was my first time playing through Mass effect 1, I had no idea and left the planet after killing the rocket and sniper troopers. I have completed the other 3 outposts but can’t finish because of the one in Maji.

What I have tried so far:

• Killing myself using grenades
  • I thought it was going to respawn the enemies but didn’t work.
• Leaving and returning to Maji via the Normandy
• Was going to an earlier save file but I didn’t check I was trying to save an existing save file and instead of loading, I overwrote the save file. The other manual save file I have, I lose 9hrs of progress.

Looks like I have to miss a side quest.