After the Marshmallow update, my Samsung S5 randomly at any time decides to restart. Doesn't matter what battery percent, if the phone is hot or cold in temperature (never hot). Bought new battery, still does the same thing. Can be in any application. Happens no matter what number of applications are being used at the same time. Happens if only 1 application is open and restarts when that 1 application is different. Does not happen at a specific amount of time, like every 10 hours, it is random. Started happening as soon as the Marshmallow upgrade. Not once before the upgrade.
Also has problems with the dictionary. I type words correctly in a text or email and it changes it to something that is not even a real word. Only happened after Marshmallow upgrade. And as soon as the upgrade.