It's called dust
and it's been discussed a lot. yes, it's annoying. hopefully will be fixed in updated versions.
I'm using 3.3.2 and it rarely (very rarely) happens. Much more common on version 4, I believe.
My advice: manually get it out of your dust position: make a small (0.0005 or 0.00005) buy to add to your dust... then you can sell it all.