Fix extent for repeated 300 with multiple Subfields

[maipet]

Adjust replacement of brackets

[maipet]

I didn't get it 100%, maybe @TobiasNx can help?

[dr0i]

Could solve it by print-debugging - i.e. insert some identifiable messages in (here) replace functions and let the tests rebuild the data anew with mvn clean install -DskipTests=false -DgenerateTestData=true. Then git diff and search for the messages. If you know which statements should/could provide the missing bracket (or which variable is involved and trace that variable) it's not so far from try-and-error-until-resolved.

[TobiasNx]

I did not find a corresponding issue for this. We should add issues for upcoming changes in the scrips if they result from errors to better document our progress.