Ok.. I accidentally commited about half of the changes to 8.1, without the other half (I did a 'git push' but aborted almost directly when I noticed it was pushing 8.1. However, it seems aborting does not stop the commiting, and in this case a lot of the commits were not actually included).
To fix this I just did a merge of the string split to 8.1. I assume there are alternative solutions, but there had been other commits done as well, and the merged commits are spread in time (some are merged), so in order to fix it quickly I just basically did the full commit.