Gears not clicking in fast - Some help please

Conky

My bike seems to go into most gears ok but sometimes I will be riding and it will change gear without me me doing anything.

Also in one of the gears it may take a few moments to go into gear.

I only have a 8 speed gear system, shimano deore rear changer and rear cassette and a single dmr on the front.

Is this a changer issue or could it be my chain?

Thanks