Hey @deano86 ,
happy to have a look at this with you. Can you please confirm what app are you referring to and if you are using this for prolonged periods of time when that happens? Can you also tell me what phone and software version are you using so I can provide you with the right steps to try to get this sorted? You can find the model at the back or from the phone Settings> About phone, and the software from the same path Software information.
