Hiring oddities

For some reason, when ALL of my corps reach a hiring of 100%, the next month they all go down to 90%, some go down a bit further down, and then they all march towards to 100% only for this cycle to repeat.

Anybody experiencing this?

I think so but I assumed it was a low lvl worker shortage

It can happen when the number of unemployed in some groups of workers is very low.
In such cases, the natural fluctuations cause a small shortage and employment falls, then there are enough unemployed to grow again.

maybe increase the population a bit.
I never say it in countries on TA but these have many unemployed.

which country is it?

Terminus.