Its probably a bug, I have the same Problem
Addendum
Affects versions:
(1.21.5) → 25w07a - 1.21.5
(1.22) → 25w15a, 25w16a
I see that different, which is why I reported the bug
@Ceresjanin123
Nah in 1.21.1 and before the Minecart behaves differently there, it only jumps far up without rails but not with rails (Rail, Powered_Rail, Activator_Rail)
except the Detector Rail
@ joey
Instead of giving a reasonable answer why it could work for you e.g. because some conditions could be different or settings you give an unhelpful comment