Why does Huawei P20 Pro restart running app when I unlock post-run?

[Android Central Question]

Can't figure out why phone restarts running apps when I finish a run, without recording what I've just completed. Used C25K, 5K Runner and BBC Get Inspired apps and they all refresh/restart when I unlock phone so no run data recorded. They all work throughout the run with prompts and audio combined but I must be doing something wrong when I unlock my phone to see how far I ran. Think the problem is related to the phone/me rather than the apps. Any help much appreciated.