Exceed recommended operating condition

My guess would be that you would take the device outside of its operating spec - i.e. your timing might be affected, it could get too hot eventually, draw too much current etc.

I think the absolute max ratings means that permanent damage will occur if you take the voltage to that point at all - i.e. if you take the input above 3.6 V temporarily then the device might not work properly but when you take the voltage back down below 3.6V then it will behave as normal. If you were to take it even briefly past the absolute max then the device might / is likely to suffer permanent damage.

If you continually operate the device outside of the recommended range then you may eventually damage the device but I don't know this for sure; or for how long you'd have to run to do this.

If you're desparate to know then I'd raise a query directly with Altera - I assume that you're asking out of interest - i.e. not because you're planning on designing with the device operating beyond its recommended limits - I think you'd be on thin ice doing that.