Check this thread out. There are several more, but this is one I remembered.
Not sure of the logic of uninstalling/reinstalling Navigraph etc. For the most part, it’s just database files where the apps just do lookups.
I began noticing the offset after one of the updates as I was airport hopping across the country. I was in APR mode, came out of the clouds in solid IMC and was way off to the left even thought the needles said I was dead nuts. Had to take the miss and manually correct as I recall. Can’t remember which airport. I’ve was at many on that 3 month trip.