command tab application switching scrolling to end of open windows

Hi all:

I'm not sure what started this, but just recently I noticed that if I use command+tab to switch windows, and by this I mean holding command and *tapping* tab 1 time, while continuing to hold tab, here's what happens: the application switcher starts on the first window on the left and scrolls all the way to the end of the open window list at a speed of about two application icons a second. If I let up the command key on the right one, it will open that window, however the speed is very fast and it's basically a guessing game if you can get the right window.

I heard this behavior was observed by some others having trouble with mouse-related drivers in a much earlier release of OS-X. The reports I read dated back to 2014, but they were this exact problem. I do not have a stuck key (the tab key is operating fine). I am using a Macbook Pro 15" Retina 2014 running 10.14.6. I did a supplemental update and reboot this morning, still having problems. I am using an external mouse, it is an ACTME USB wireless mouse. I am using the laptop keyboard. I do not have any other peripherals attached.

I have looked through the settings / preferences intensely to try and locate what the problem might be or if this is a new setting or behavior. However I cannot find anything regarding command + tab application switching.

Can anyone help?