Coolant Top Ups

My ev9 has 44,000km (27k miles) and 3 times I have had errors relating to low coolant levels.

The first time I figured was low from factory. The second and third time the car wouldn’t charge overnight and had the cooling fan going at max when I got up in the morning with different alerts each time.

Each time I have brought it in and they have found no leaks, topped it the coolant off and that solved the problems. They basically told me I should be watching the levels regularly. It seems to take 3-4 months for the coolant levels to drop low enough to cause issues.

Has anyone else who drives a lot been experiencing this? I have no drops of anything on my garage floor to suggest a leak.