Anyone know how to maintain a persistent MTP usb connection in Marshmallow?

hmm... which setting is that?
It is set as MTP but on plugin it asks which options.

Developer options --> Select USB Configuration

I've had it set to "Charging only" on some occasions, but once I manually set it to "MTP (Media Transfer Protocol)," then it sticks.
 
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That's my question; It is set as MTP in Developer options but "Charging Only" is always the default upon usb insertion.
I've had that happen to me a couple of times on the stock MM. I remember manually changing it to something else and then back to "MTP" for it to stick.