Yatse crash and need reboot the smartphone when ...
Since several versions Yatse crashes when you clic on the picture "ear" to choose the sound track or the picture "subtitles".
You watch a video and you stop it. Now you watch a new video and you want to do know if DTS or AC3 is possible; at this moment Yatse crashes the display is blinking.
and needs to reboot the phone.
My smartphone: Honor 5c, android 7.0
I can only suppose you have activated the option Disable keyguard and are using Yatse when screen is locked.
You are facing an Android bug, there's no known workaround. You can recover without reboot with quick pressing of home at correct moment but very hard.
You should disable the option until they fix that, usually notification on lockscreen is enough.