This might be related to the issue I just discovered.
It looks like traffic totals no longer caps off the max entries.
So e.g. hourly should only show last 24 hours, Daily last 28/29/30/31 days and so on.
On my local unit If I wait long enough the hourly shows up and its got over 40k hours of data on it.
To see if it is just a local unit problem (corrupt database etc.) I checked another pfsense install and it is also above 24 hours. So looks like this package might be broken on new builds of pfsense, as it used to work properly originally.
In addition my local unit has many hours as 0 bytes of data, it is consistently <value> 8 hours of 0 bytes <value> 8 hours of 0 bytes <value> and so on.
--update--
Actually my issue might have been different.
I noticed I had device files in the vnstat database dir for devices that shouldnt be tallied, I disabled graphing, deleted the files, turned it back on, and now it is cutting off excess entries again, although I have lost all hourly and daily data (I assume due to them been corrupt), monthly data is instact so not end of the world,
The other unit has no device files at all in the directory, just the main database, so not sure what is going on with that one.