Analogue Stick input just slightly off sometimes

[Bluster Kong]

Sometimes when I'm playing recalbox with my Wii U pro controller and my delock bluetooth dongle, the input is just slightly off.
Like when I stop pushing forward my character is still walking forward, or sometimes it's registering me pushing the stick down.
This can get really annoying and I want to know what I can do against this.

[Bluster Kong]

Sometimes button inputs seem to be off as well.
Can anyone help me with this? It's actually severely hindering my experience