read through the known bugs and didn't see anything like this so i'm going to post this
i used the electric jet pack till it ran out of energy then after it ran out of energy i was using dynamite to dig down to bedrock for fun and i took some damage from one of the blasts and it recharged the jet pack? i used TMI'd items if that makes any difference i don't know what to put in a picture so if you want to get a picture of a certain thing tell me and i will take a picture.
how to reproduce this error: use a completely empty electric jet pack and stand on dynamite then set it off i guess it damages the completely depleted jet pack so it starts over
not sure if this is the same with the fuel jet pack.