It didn’t affect the outcome of the game but here https://online-go.com/game/3345799 despite setting the living groups correctly it didn’t give 4-5 points in the bottom right of black’s top right group.
The automatic scoring is a bit buggy, yes. (There are several forum threads regarding this problem.) And the score estimator is indecisive. (I advise against using it altogether.)
You should always make sure that you are accepting a correct score. If the score is not correct, you should adjust it by clicking on groups/stones/dame points until the score is correct. If you and your opponent can not agree on the correct scoring, call a moderator from the sidebar.