Charging the battery from the smartphone?

The battery of my Huawei p20 lite sometimes charges slowly or stops charging at around 40 percent. Then again it charges 100 percent at normal speed. Why is that, does someone here have similar problems with their Huawei smartphone?

Your jack on the phone may be dirty. I also had it on my Huawei. Use a very thin wooden stick to get the dirt out. Carefully, only do this if you are patient.

Do not bend any pins then test again

DO NOT TAKE METAL