big cursor just gets bigger

the action to toggle the cursor size has stopped toggling, the command I used to use to do it now just keeps making the cursor bigger, I have to restart the machine to get a normal cursor back

Which version of BTT & macOS?
What do your settings for the action look like?

Maybe you are not using the Toggle action but the "Set Cursor Size" action.

In a previous version I had the same behavior using the "toggle" function. In version 4.401 it makes the cursor bigger and then nothing - no toggle. I have opened another bug report with more detail in the hopes that this gets fixed.