In many cases, many people are working on the same issue without proper communication and are submitting multiple PRs. Can the moderators assign the mentees to their issues and keep a waiting time of 1-2 days for the respective PR.
It becomes disappointing when you spend considerable time on an issue, only to suddenly see a PR linked from a person who hasn't communicated at all beforehand. It also helps skim through openly available issues.
We tried this last year and it was a disaster. People said they would work on an issue, we assigned it, and nothing. Then there were a bunch of comments from others who wanted to work on those issues, so basically these issues had comments about who's working on them and whether they had been abandoned and in the end, nothing happened.
So this year, just submit a great PR. If there are several PRs for the same ticket at the same time, we'll pick the best one. Proper description, test cases, code, ....
Additionally, even if there are multiple pull requests, and we don't pick yours, we'll still take it into consideration for GSoC. So in any case your work will count towards your application, so don't worry too much about possible duplicates.