Ok, so let's test alien at 1:130:14
I cleared all systems: 1:128, 1:129, 1:130, 1:131, 1:132.
So I cleared 2 systems each side next to the alien. Funny thing is that at 1:127 and 1:132 there are also two 5 star aliens. So there should be a lot of rubble fields in that area. I will check that 5 system every hour to see if any rubble fields are there. In the meantime, I'll probably be attacking the alien to see if that will help in any way.
Checking history (hour - rubble fields):
22.11.2022 19:10 - no rubble fields at 1:128, 1:129, 1:130, 1:131, 1:132
22.11.2022 20:20 - no rubble fields at 1:128, 1:129, 1:130, 1:131, 1:132
22.11.2022 22:17 - no rubble fields at 1:128, 1:129, 1:130, 1:131, 1:132
22.11.2022 23:24 - no rubble fields at 1:128, 1:129, 1:130, 1:131, 1:132
23.11.2022 00:12 - no rubble fields at 1:128, 1:129, 1:130, 1:131, 1:132
23.11.2022 01:17 - no rubble fields at 1:127, 1:128, 1:129, 1:130, 1:131, 1:132, 1:133 ( 2 new system cleared, let's keep going )
23.11.2022 02:28 - no rubble fields at 1:127, 1:128, 1:129, 1:130, 1:131, 1:132, 1:133
23.11.2022 03:18 - no rubble fields at 1:127, 1:128, 1:129, 1:130, 1:131, 1:132, 1:133