We suggest that everyone follow the Versioning conventions as you imply (bug fixes in maintenance versions, backwards-compatible features in minor versions, and backwards-incompatible changes in major versions).
If you went from 2.0-beta to 2.0.1, then all bets are off. There are no guarantees about features from beta to final release.
If you went from 2.0.0 to 2.0.1 and found non-backwards-compatible changes, then that does represent the convention being broken. Either the conventions were broken for a good reason or by mistake. It’s certainly reasonble to assume that going from 2.0.0 (non-beta) to 2.0.1 or 2.1 should not break scripts.