Which model Mac do you have?
If you have a can of compressed air in the office, suggest that you use it. Your keyboard may be dirty-crumbs, dust balls, etc trapped under the keys. Especially so, if you eat while using the computer.
If you need to pop the keys off to clean, check out the following link:
iFixit
Search YouTube for _Your model Mac_ “How To Clean Keyboard” tutorials.
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