Troubleshooting: Toolbox hotkeys stop working & Selection Tool keeps jumping back to grab tool

Hi Everyone! Thanks in advance for your help. I’m a new animator to Blender and I suspect I’m accidentally hitting some hotkey combo that is making my toolbox behave strangely. When things are working properly, the hotkeys I’ve attached to select (b), move (g), rotate ® and scale (s) will activate that tool. What mysteriously happens from time to time is that I can no longer activate the tools unless I click on the toolbox icons. I’ve tried deleting the hotkeys and resetting them, but that doesn’t help. In addition, even if I click on the selection tool in the toolbox, it will automatically jump to the move tool as soon as I release my click. The only fix I’ve found so far is defaulting back to factory settings. This can’t be a part of my permanent workflow! If anyone knows what I’ve done and how to fix it, please let me know!!!