Since I expect this is one of the main features that users would like to use, it is remarkable that academia.edu have not fixed it for so many years - especially when it's not much development work to do so.

Another fix would to be allow people to say yes or no to suggested mentions en-masse or in bulk. This would be easy to do in various ways but one easy tried and tested solution is to put a check box next to each entry in the list of suggested mentions and then allow people to check all for say 100 at a time plus check/uncheck manually and then select yes or no for all checked entries.