I have been messing bout today with similar issues. think i may have a solution...
open up a clip in PRV. right hand corner where snap blue button is, click the little arrow pointing left. Choose your required snap setting (1/16 etc). Then left click the 1/16 value so that it is not blue. Unblue the midi and other symbol as well.
Basically set the snap setting and ensure the snap button in prv view is not blue asnd you should be ok.