The PR bot has two places where the PR title is parsed to extract the bugId. There is one in CheckRun which attempts to rewrite the title to conform to the established format. There is another in Issue, which just extracts the bugId for bug association. The discrepancy between them is that the former does not detect a title on the format "bugid : title", note the space before `:`, while the latter does. So if a user sets the title with that format, the bugid is correctly extracted and associated, but the title is never normalized, even though it could be on the JDK-NNNNNN form instead of the standard NNNNNN form.

Example PRs:

https://github.com/openjdk/jdk/pull/28312
https://github.com/openjdk/jdk/pull/27301

I think the best fix would be to extend the title rewrite logic to match with white space between the bugid and colon so that it can normalize such titles.