Does the internal energy increase during the boiling process?

During boiling, the internal energy does not increase in all cases.

1. If during boiling the mass of the liquid decreases, then the internal energy will also decrease.

2. If the vapor was previously a liquid, then the total mass of the evaporated liquid and the remaining liquid will remain constant, the vapor molecules in the “liquid + vapor” system will move with a constantly increasing energy than in the initial state (liquid).

In the first case, an option is considered with a decrease in internal energy, and the second with an increase in internal energy.