I have been playing Caesar 3 for a long time and now I have it on gog; which is a good thing. However, something keeps going wrong that did not go wrong previously. I build cities with excellent housing blocks and plenty of labour and everything runs along smoothly until for some reason I get labour shortages. Where do these labourers disappear to?
Previously this problem would only occur after years and years, maybe even decades, on the same city map, but now it starts after just one year.
What is happening and has anyone else encountered this issue and how did you solve it?

The aging workforce is the main reason you start to lose more and more works several years into the game, but it certainly isn't supposed to happen after only 1 year. If it is a bug I've never encountered it. Are you sure you didn't at some point see a bunch of people leave dragging sacks behind them? If something like a basic service (water, food, entertainment etc.) gets interrupted for too long then a whole swathe of people will leave like that, and often I find it is then very difficult to get people to immigrate again. Then I usually restart or load a save. You should be able to see the after effects of this : lots of houses far from maximum occupancy

Are you getting Villae after just one year? Patricians do not add to your workforce, and in fact the command that they hold over Plebs subtracts from your workforce.

Make sure that you have more Insulae and/or Casae than Villae. Cut back on the Gardens and Plazas near the Insulae if you have to, or make sure that there's no Barber near the Insulae to ensure that you have a high enough Pleb population both to serve your Patrician population and to carry out the usual tasks.

The game I was playing where I noticed it was on hard, so I've been running some tests in Brundisium on Normal difficulty. I have a population of 563 with a total workforce of 265. In 342 BC I have 2 unemployed, in 341 BC 3 unemployed, in 340 BC 2 unemployed and in 339 BC I am 1 worker short. In 338 again 1 worker short. So I destroyed and replaced all housing and by April 337 BC all housing was fully occupied, but now I am 26 workers short!
If I don't destroy the housing and just keep things going, in 337 BC I am 3 workers short and in 336 BC I am 7 workers short. I haven't tested it beyond that.
(How) can I upload the saved games?