Hi - I think this may be related to the recent update in translators but I am not certain.

In any event, the checkboxes to select which citation to import are pre-populated when using PubMed but not when using PubMed Central.

Example here:

https://www.ncbi.nlm.nih.gov/pmc/?term=platelet+rich+plasma


See this image:

https://www.dropbox.com/s/7nbw9jwpom8ln8e/pmc image.png?dl=0