There is some bug with landgrabs with Dict government in 1a. In a PS you are getting significantly fewer buildings then in an SS (even though you still get a 50% increase in empty land). Here are the raw attack

9/1/2024 15:49:02 Gormtrooper (#47) Mercs Johnny Hawkins (#103) SS 168 Acres / + 128 Acres
9/1/2024 15:48:39 Gormtrooper (#47) Mercs Johnny Hawkins (#103) PS 310 Acres / + 149 Acres

The PS hit first, and I got (I believe) 78 acres with buildings on it, the SS hit second (target was formerly fresh) and I gained about 110 buildings.

I tried this on 3 different countries with the same result of far less buildings captured. I believe the dict ghost acre bonus is subtracted on a PS (instead of added) somehow.

The buildings I gained initially should have been 78/0.67*1.33 = around 155 using straight math to convert the +30% bonus to -30% penalty. which is about a 50% increase on the amount SS gave.

You were probably capped.

What was your land at the time? How many units did you send?

Not a bug. As ugo said this is exactly what would happen if you were capped and hit at about the break from both hits.