So I am keeping on this as well but we have some to add. Zenith was having this same issue, and we decided to test plots outside city walls and inside city walls. We have been stuck at 1000 for a while. I bought a plot outside city walls placing down a 3x3 which according to the blueprint should add 75 prestige:
After building the house we stayed at 1000 Prestige. We then decided to place down a 4x4 personal plot inside the city walls and built that which should give 100 prestige according to blueprint:
After we built that up we ran back to the city hall and checked and our prestige was now at 1100:
After we did that we built the siege workshop which should also increase the prestige by 100:
In the time it took to build that our 1100 degraded to 1030 and our Residents dropped to 9 but the prestige from the siege workshop was there.
So we decided to test again and see if a dupilcate 4x4L building inside city walls under someone elses' plot would work for prestige! After placing the blueprint down for 4x4L building we checked city management and we were still at 9 residents but our prestige was down to 1100:
After we built the 4x4L our prestige jumped to 1200 but stayed at 9 residents. We are going to keep an eye on whether the prestige degrades or not, if it does then it has to do with personal plots inside the city walls no longer counting as residents. I will edit this message with the update on whether or not it degrades.
