GOES-17 first light on GOES-16 HRIT?

Going back and looking recent decoded imagery from my GOES-16 HRIT downlink, I noticed a number of mesoscale (M1) image files with "G17" in the filename.  Upon investigation, these turned out to be infrared images of Baja California from the GOES-17 satellite, currently parked in a checkout position at 89.5°W longitude.

GOES-17 Shortwave IR (Band 7) M1
2018-07-10 1500 UTC

The shortwave IR (band 7) images above from clearly show the northwestern Mexican coastline at around 1500 UTC on July 10.  The longwave IR (band 13) images shown below, however, show some severe banding artifacts that could be related to the ongoing ABI cooling problem.

GOES-17 Longwave IR (Band 13) M1
2018-07-10 1500UTC

Due to reliability issues and disk capacity in my current environment, it's impossible to determine if these were the first GOES-17 images to be sent on the GOES-16 HRIT, or just the first ones I noticed.

The data seems to have continued arriving over the past few days without stopping.  The latest longwave IR imagery shows much less severe banding despite the same time of day.  This is pure speculation, but perhaps NOAA has a partial solution to the cooling issue at hand?

GOES-17 Longwave IR (Band 13) M1
2018-07-14 1500UTC