You did not mention if you have a cable or an aluminum rod pull.
If you have the threaded aluminum rod it is less common to have problems. Just remove and replace or clean the valve. Probably some tp stuck in the valve track.
If you have the cable pull it is much more common to have problems shortly after you buy your unit. Not because there is something wrong with cable pulls, but because of the quality of install. The binding and play causes the valve to not quite close.
I often have to repair newer cable pulls for this issue. Quite often the manufacturers will take a universal cable that is too long and then coil it up in the underbelly. This causes friction and the valve to pull and close hard.
In the field I remove the cable and lay it straight.
Measure the throw or length that the inner cable sticks out beyond the cable housing. This dimension changes with each size valve.
Remove the inner cable.
Cut housing to correct length that is actually needed to minimize binding.
Install inner wire and cut to proper throw.
Reinstall and you will be amazed how easy and smooth that cable pull works now.