My MagSafe battery pack doesn’t work until plugged in??

I bought my MagSafe battery pack about 2 months ago. Since I purchased it it has never worked right. It only will charge my phone until it is plugged in first. Even if it charged to 100%. The photos attached is just an example of what I’m experiencing. The first picture is the MagSafe battery pack connected to my phone, showing 0% battery life. The second picture taken 2 seconds later shows my battery percentage of MagSafe battery pack to be 12%. It should work without having to plug it in prior to use. Anyone else having this issue? If so, if anyone has any resolutions, please let me know