The ramp/patio doors are made by Lippert Industries and are not "Keystone specific"... You'll find the same doors on most brands of RV's.
You can download the Lippert triple play owner's manual here:
https://lci-support-doc.s3.amazonaws...cd_0001379.pdf There should be a copy of this document in your trailer owner's packet.
In the Lippert manual are these statements:
Note: While the product is water resistant, it is recommended to store the door in the closed position during periods of rain to reduce the risk of water intrusion, which may result in delamination.
CAUTION Always close ramp door when raining. The open ramp door surface is not water resistant. An open ramp door will absorb moisture increasing the weight of door and making it more difficult to close and increasing the risk of water intrusion and possible delamination.
If it were "my" $75K investment, I'd be "exercising the close feature" if there was a hint of rain or even heavy condensation overnight..... YMMV