I don't understand the outcome of the solution for a circuit with two voltage sources and an inductor
First, you draw your current I with a reference direction to the right.  So, this current I is (V1-V2)/j5.  That will correct your phase angle.

Second, to calculate the power quantities coming from source V2 you need to use -I which will just be I with angle shifted by +/- 180 degrees.

See if that clears it up for you.