It is intentionally changed to lowercase to facilicate copying into commit message after conventional commit verbs.

I see. As far as I know lower case isn't required for conventional commit message after the verb. I guess you just see it everywhere because of English language. But even with English language this can cause trouble. Personally I was annoyed by it because I often have issues like NPE in class.method:line or IAOBE in class.method:line. Copying these messages and making the first letter lowercase is bad then.

Also in other languages it feels unnatural to start with a lower case letter, even in commit messages. I have just taken a look at our commit messages of different developers and they all start with upper case letter after the conventional commit verb. For example in German nouns are always written with upper case letter. If commit message starts with a noun having a lower case letter it is wrong.

Maybe make it configurable?

You are right that the convenentional commit does not put any restrictions on commit subject cases. Will revert it back.

State changed as code fixing the issue is committed (ea20d4eb)

State changed as build #4330 is successful