Quick note on this topic that may be helpful to others.
I finally had my 2019 Explorer Sport in for service late last week for a number of items, bad map sensor on intake manifold, that put car into limp mode - yikes! As well as recall/TSB for ABS brake computer update, fixing the roof rack rails from popping up, and the NO GPS Sync3 issue in this thread.
Given the intermittent nature of the NO GPS icon, they had a hard time replicating it - but did get lucky and saw it. Some notes from what my local dealer did:
1. They kept tying to replicate it and got lucky and saw it - checked my APIM it was good. Checked the cables from the APIM to antenna, and the splitter and they were all good.
2. They went into the debug mode in Sync 3 and checked the satellite signals - I had done this before too - one thing of note, it was only connecting to/picking up signals from a handful of satellites, and it should have been picking up way more. (As of August 2019, 74 Global Positioning System navigation satellites have been launched, 31 of which are operational, 9 in reserve, 2 being tested, 30 have been retired and 2 were lost at launch. The constellation requires a minimum of 24 operational and the official target count is 33.)
3. The called Ford techs directly and talked about the issue and found some commonality to it, it should definitely pick up more than 8 - which is what I was seeing when it was working, more than 8, less than 8m and it would drop out show NO GPS icon - they gave some guidance but not much.
4. Tech went to back of car, and banged on/tapped the antenna during usage, and sure enough it would cause the signal to get worse or drop entirely.
So, it looks like its bad antennas - either they are faulty, getting damaged somehow (maybe water/car washes, etc). And this is the shark fin style with the added antenna coming out. I know different models have had different antennas over the years.
Ford overnighted a new antenna to dealer with paint job to match, popped it in - and fingers crossed it's fixed it so far - and it feels like its much more responsive in course-correcting if I go to areas where the map coverage has changed - before sometimes it would take quite a bit of time, or merging back onto a nearby road or highway for glitches to get you back on track/tracking properly - now it feels quicker, likely from the broader amount of and more stable pickup of the signals from more satellites. If it happens again, I'll be sure and share. Looking good at the moment.
Also - its worth noting that although the government hasn't used/triggered SA - (Selective Availability) since 2000 when Clinton eliminated that for more localized techniques to degrade the civilian GPS signals in times of need (military actions, presedential traveling, etc) - there are still things that actively are triggered by the goverment that can effect GPS from time to time - a really handy page, especially if you are doing diagnoses to see the satellite strength during testing and what's responding, is to use the governments GPS status page here, which has current status on all the satellites and any operations or programming that might be occurring or planned that can cause a variety of issues - take a peek here:
https://www.navcen.uscg.gov/?Do=constellationStatus
Hope this is helpful!