Can confirm in 1.21 Pre-Release 2. And in this version it is also possible, after reloading the chunks in which the minecarts move, that they bug into each other, or are out of alignment. I observed, that one minecart was misaligned by one block further away from its leading minecarts in front. And after all pistons have pushed the stripped oak logs, all minecarts, also the misaligned one, were aligned properly again as if nothing happened.
I can confirm that MC-2783 describes this issue.
However I searched and I had not found anything regarding this issue at first.
I searched under "minecart misaligned" for example
@Southpaw#1496 Hello Southpaw, This is what happens to me! But with the difference that I get ejected but you not.
Thanks @tryashtar for helping. Finally the Stone Patterns on the map disappeared.^^
1.21 Pre-Release 2: when reloading the chunks, if one minecart unit (of for example 10 minecarts), some minecarts might bug into each other. This is as if one minecart is moving, but with a way darker shadow.