Why is there lag time with the 'back key'

[Android Central Question]

I am using android Oreo on Sony Xperia XZ (F8331) and I am experiencing a delay when using the 'back' button in some apps especially the camera. Is this a common issue thus far?

 

[B. Diddy]

Welcome to Android Central! Does this also happen in Safe Mode? https://support.sonymobile.com/global-en/xperiaxz/kb/0231018877589a7b01429399b11c00699b/