Box not stying in same place issues

I'm having issues with the box tool, when I draw my boxes to highlight my areas of interest on the ctrader mobile app sometimes when I come out of the app and go back inside to look at the charts the boxes have moved and are not in the same place where I placed them. 

I have tried locking them in place with the lock icon that seems to help but It still does it evey now and again can anyone help me with this problem?