I started a small trip with 51%. ABRP said, I would reach the destination with 39%. I have no live connection (yet). During the trip, ABRP reduced the target estimation bit by bit to 32%. I wonder why the initial estimation is so different from the en route estimates. I didn’t drive fast: 50 and 80 as allowed and 110 where 120 are allowed.
(I reached my destination with 35%.)
Without any live data input, the plan updates we do while driving are a bit sensitive to small errors. There could of course be changes like weather and traffic, but what you experience is probably due to a long string of rounding errors. We will investigate it more.