Apple Pencil 1st Generation charges and then randomly loses charge progress

Hello,

I don't have any issues with pairing or working my device luckily but I just wanted to inquire about something that concerned me. While I was using my device, I received a notification that the Pencil was on 3% battery life so I of course plugged it in. I waited a while and it had not changed very much at all but eventually started to show that it was almost done charging. However, when I looked at its charging status again a few minutes later to see if it was done, it had gone back down to 6% out of nowhere. Currently, I just restarted my iPad and now the pencil seems to be charging pretty quickly, however it almost seemed "stuck" on 78% for several minutes. It was going up in charge pretty quickly until a moment ago. I unplugged it, plugged it back in and now says its at 81%.

For clarification, since I've purchased the pencil about a month ago, I have not gone more than a few days without using it. So my question is, to avoid having future charging troubles, does the pencil need to be charged whenever it is not being used? Now that I've researched it I'm seeing that if the pencil sits for a while without actively being charged then the battery will simply just dies because it is too small. Also, I purchased this product from Target and wasn't sure what that means in terms of the warranty if I ever needed to fix it. Any answers are appreciated thank you!