Mine did that the other day when using my 13 mini, the only device I had connected to an Apple 35W Dual-Port Adapter (my typical charging setup, other than an Apple MagSafe Charger + 20W Adapter).
Right now it is once again on the 35W Dual-Port and trickle-charging at 99%, taking its lovely time and nearly cool to the touch on the back. I respect and find endearing that you only charging with a 5W Adapter…that is the real 🐐 G.O.A.T…but I also tend to love and trust Apple’s proprietary charging tech and don’t shy away from enjoying perks like fast-charging and/or MagSafe within that framework.
Amazing that after nearly one year after acquiring the 13 mini and heavily charging/using it this way the battery health has held up like it has (currently 94%). In my experience Apple really did an excellent job with 13-series battery chemistry and engineering over the 12.
Also I will deeply miss Lightning and wish Apple had continued to iterate upon and improve it. USB-C just feels…cheap, sorry. It’s a sharp-edged hollow shell whereas Lightning is a smooth-ended, sculptural pillar. Love my M1 MacBook Air but it’d be nice if it had MagSafe because, again, Apple’s own charging interfaces are just it for me.