If for some reason the issue is still persisting, below is the solution that fixed my issue.
This usually happens when you have an external mouse connected via Bluetooth or a dongle to the mac, and whenever mac wakes up from sleep, the scrolling function of your external mouse stops working.
Here is how it was solved by SMC RESET and PRAM RESET!
Prior to Reset:
- Press and hold the power button on your Mac for up to 10 seconds until your Mac turns off.
- Unplug all accessories from your Mac, including printers, drives, USB hubs, dongles, and other non-essential devices.
SMC RESET
- Shut down the computer.
- Plug in the MagSafe power adapter to a power source, connecting it to the Mac if it is not already connected.
- On the built-in keyboard, press the (left side) Shift-Control-Option keys and the power button at the same time.
- Release all the keys and the power button at the same time.
- Press the power button to turn on the computer.
PRAM RESET
- Shut down the computer.
- Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step
- Turn on the computer.
- Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears.
- Hold the keys down until the computer restarts and you hear the startup sound for the second time.
- Release the keys.
For video tutorials, please search Mac SMC reset or Mac PRAM reset.
This fixed my mouse scrolling issue. If it solves yours please upvote the answer and reshare.