I came across many questions which are related to unpredictable behavior of the phone. There are no logical reasons or solutions to help them. Only thing I could have tell them is to restart their phone! Can we develop a way to deal with such questions?
Paraphrasing a closure reason from Stack Overflow (emphasis mine):
This question was caused by a problem that can no longer be reproduced. While similar questions may be on-topic here, this one was resolved in a manner unlikely to help future readers.
The aim here is to build a list of solutions to problems, so if a problem happens often, or can only be solved by rebooting the phone, I'd consider it on-topic, and have an answer to that effect.
If a problem only happened once, and a reboot fixed it, then I'd consider it more off-topic.