Hey, is this still active?

It is, but updates are a little slow right now. I’m hoping to get it patched to the latest version soon.

Is it normal to have the Decadence Mechanic teeter on the edge of Stage 1 for years on end? The event slider will say it has 70 to 100 days till the first Stage (0/2400) is completed, only for the modifiers to positively change towards Iron Gold a few days prior to completion.

That's intentional, it just means your Decadence is maxed out. Stellaris doesn't let Situations sit at 100% without resolving, so the mod just keeps it at around 99%. You can resolve Decadence permanently by getting it down to zero - or by reforming out of the Stratification Protocol civic.