T5 gave good advice. I don't think a non-optimized app would do that.
I have no knowledge of JBing. New here. But, if you flashed roms when you were on Android, you know soft reboots are not uncommon.
There were always some users that could never get a flash without issues while most were fine. Sometimes user error in flashing. Sometimes just very minor differences in the phones hardware. JBing may have similar issues.
For me, I am done with any type of phone hacking. Even though I seldom had an Android issue. This one just runs too well for me--
I'm a big fan of jailbreaking (or at least was) but the idea of constraining the already heavily constrained RAM amount of iPhone 6/6 Plus with jailbreak tweaks etc is a bit crazy to me nowadays.
I have a lot of these as well (pages and pages) and had about 3 reboots so far since my replacement iPhone 6 plus (128gb) due to the same problem. Is this something we should worry about (i.e. Get another replacement)?