I have the same issue. I've just lost a minecart with chest full of items. I pushed two minecarts with chests on my railway, and it went on through the powered rails and stopped when there were no rails anymore (the railways was above the ground). One of them just disappeared. First I thought one cart pushed the other and it fell down but there was nothing, I even dugged through the area and it's gone 😞
I have the same issue. I've just lost a minecart with chest full of items. I pushed two minecarts with chests on my railway, and it went on through the powered rails and stopped when there were no rails anymore (the railways was above the ground). One of them just disappeared. First I thought one cart pushed the other and it fell down but there was nothing, I even dugged through the area and it's gone 😞