If you import/modify outside Store Manager (PS usual import) searchcron has no effect...

Hello,
I saw a post about this but now I'm not able to find it anymore...so write about it again.

1) you import products through Store Manager, this is ok
2) you modify products (eg. name and descriptions...) with the usual PS CSV import
3) then, those specific products never indexed by cron

so,
searchcron.php?full=0&token=YourToken&id_shop=x (for modified products only)
OR
searchcron.php?full=1&token=YourToken&id_shop=x (for the entire index)
has no effect at all...

why? Can you reproduce this bug and fix it, please?
thank you very much