Twice now I have had a number of minecart tracks vanish,  The first time it was about 6-8 sections both iron and gold rail.  The second time it was about a dozen.  Both times all missing track was adjacent (a single line, not here and there).  Track was laid on sand but the sand was still there as were the buried redstone torches that powered the gold rail.  Both times it was in the same location or near enough (site is an outpost with a nearly complete raid farm).

seed: -1045477181

coorid: near -2357 70 -2138