As background, my 2013 XFRS had the plastic bits, water pump and thermostat housing replaced back in March, 2023. The expansion/overflow tank has maintained the same level of mid point of the cold level indicators. Past month or so I’ve noticed the tank remains completely full up to the cap. Sitting overnight doesn’t change the level. There are no codes or dash warnings. Removed approx .5 liters of fluid but level hasn’t decreased. Hoping someone has suggestions.

A guess: you have an air lock somewhere.

If you've taken 5L of coolant out then I'd say you're running seriously low on coolant.

That’s .5 of 1 liter, Not 5 liters…thank goodness.

Thanks. Another indicator to get my eyes checked.

So it's 0.5.

I would try taking some more out and redoing the top off bleed sequence

otherwise, a full drain and vacuum fill

More than a year later of normal coolant levels, and then you have an air pocket show up? Seems unlikely.

I would do a test for exhaust gases in your coolant to see if something else is going on. You could have a head gasket issue that is just now showing up and pumping air into the coolant system. Did you overheat your engine just before the cooling system parts were refreshed? Often, the cooling system refresh is done reactively to a coolant leak that could have caused overheating.

Try a bleed if that doesn't work ,you may have a problem

Apologies if this is a dumb question, but are you sure the additional volume is coolant? Got pics?

I believe that it is as the color appears consistent. I removed the excess down to the cold level and, thus far, seems fine.
I have had 2 prior service visits unrelated to coolant so I have no idea where the excess fluids came from.