White/blueish smoke after thermostat change

[Lib88888]

Garage changed my thermostat the other day, zero issues since & no coolant loss
However on startup after overnight I’ve noticed the engine “coughs” if that’s a way to explain it, and then some blueish / white smoke comes out the exhaust. Smells sweet ish like coolant,

Other than that drives fine, no coolant or charge in oil.

Any ideas?

 

[RenKJ]

generally blue means burnt heavy oil and white can be coolant or light oil amount