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Does some of the chart show up, and is it just details that are missing, but does the device show or the software show, where you are and where the nearest coastline is more or less, even if soundings are missing ?
What platform - or, device, or computer - are you viewing the Navionics charts on?
In other words, the coastline 'definition' is degraded, or lessened.
It's hard to say whether the soundings around Jonesboro are simply in poorer shape or what, but the degradation of coastline definition and detail is definitely not owing to lack of chartings... since coastlines are defined by satellite views nowadays, whereas sounding require someone to be 'down there' on the sea taking such data.
So I think something's wrong.
I suggest first, that you restart your iPad... or better, shut it down, not just suspend it.
Then let it cool off for a while... about 15 minutes to 1/2 hour should be enough.
Then start up the iPad again, load the Navionics software once more, see if the near-Jonesboro Maine area is once more in good shape with all details apparently there.
Probably just a glitch. Hopefully it does not mean that your Navionics file is corrupted.
On the assumption that it is a glitch, I recommend turning Off/Shutting Down the iPad for 15 min. or longer to cool off.