quantisize problem?

I have a problem that I suspect relates to quantisizing. When i attempt to edit an event on a track - by drawing in or resizing an event, the length is not precisely what I intend = but seems to travel to the closest line. Similarly the cursor does not stop at a precise location but seems to stop at the nearest line/marking, unless i type in the precise location on the transport bar This seems to be a problem with one song and not others, and I assume I must have accidentally triggered the Q function - which i do not usually use. Attempts to turn off Q has not solved the problem.
Thanks for your help

I hope you already worked this out but this feature is called “snap” and can be toggled with the button that has 2 arrow heads pointing to a line between them.