I am an engineer but not a EV or even battery expert so being an engineer has little to do with it
The quick answer to your question is: No. It is not a problem for your battery to sit fully charged
. When your car says 100% charge it's actually about 90% charged. and I don't remember what the low end cut off is but I think it's about 5% charge when the car shows 0%. The FFE has some built in "protection" for battery longevity by preventing a full charge or discharge.
The little knowledge I have about the FFE's NMC Lithium batteries or lithium batteries in general is that they don't like to be fully charged or fully discharged. Deeply discharging and leaving them at this state is much more detrimental to battery longevity than leaving it in a fully charged or nearly fully charged state. A battery expert familiar with our battery chemistry could probably tell you what the best SOC (state of charge) range to keep the battery in for longevity. I'm going to guess it's something like 40%-60% or maybe 40%-80%. I'm probably a little high on the low end.
The short distances I usually drive allow me to rarely deplete the battery below 40% before charging. I generally try to avoid letting it go below 20% but I don't fret the handful of times a year I have to use nearly all my capacity since that isn't likely to cause much degradation. I do however ensure that whenever I do run it nearly out of juice that it is plugged in a charging at my destination so it's at a very low SOC for as short as possible. On the flip side I only use value charging to delay charging until right before I am likely to need the car again. If it's much below 40% I usually switch to charge now since leaving it at a low SOC is more detrimental than leaving it sit fully charged. However 100% fully charged in our case is in reality 90% SOC which adds a margin of safety on the high end.
I guess what I'm getting at is with the "buffer" already built in by Ford, leaving it fully charged all the time vs waiting to fully charge until right before you will need it again probably would have a negligible difference in battery degradation. However, always letting the battery sit for hours every day at very low SOC waiting to value charge instead of charging immediately upon arrival probably would result in a measurable battery degradation. As I mentioned early I'm not a battery expert so I don't have the knowledge to put any sort of numbers to my musings. I only know what I read on the internet!