Some time back there was in media some issues highlighted about Xperia Z5 Compact regarding the touch sensitivity of its screen and particularly this issue only arises in a white color version of the handset. The Sony has acknowledged the problem and is resolving soon, maybe in a week.
The company has issued the statement regarding this issue, "We are aware of reports of a limited number of customers experiencing touch input issues on their white Xperia Z5 Compact devices." However, they further said that the other color versions of the devices are free of this error.
The company agreed that it was a problem related to software and now they are issuing the update to rectify this fault within a week. All handsets may not get this update simultaneously and timings may be from region to region.