Based on what you provided, it does sound like you're dealing with a software-level or Bluetooth stack issue rather than a hardware failure, especially if the left-click recovers after a power cycle and movement/scrolling continues to function. The A1657 Magic Mouse is usually pretty reliable mechanically, and mechanical issues tend to affect the entire click mechanism, not just one input.
Given you're running macOS Sequoia 15.3.2 on an M2 Mac mini, there have been sporadic reports of Bluetooth-related oddities across Sequoia builds, especially around wake-from-sleep behaviors. Apple often tweaks Bluetooth power states and HID event handling during sleep/wake cycles, and it's plausible the OS is occasionally failing to reinitialize all click functions properly upon waking. Your observation that the left click issue appears more often after waking further reinforces this.
Here are some things you might try:
Reset the Bluetooth module (macOS)
- Go to System Settings > Bluetooth, then toggle Bluetooth off and back on. This restarts the Bluetooth daemon without needing a reboot.
Reset the mouse's Bluetooth pairing
- Remove the Magic Mouse from the Bluetooth list entirely.
- Reboot your Mac.
- Re-pair the mouse from scratch.
Test in a new user account or Safe Mode
- Create a new user account and see if the problem persists. This rules out user-specific plist corruption.
- Alternatively, boot into Safe Mode and test the mouse after waking.
Check for background software conflicts
- Apps like BetterTouchTool, SteerMouse, or other input remappers can sometimes interfere with normal behavior — especially after macOS updates.
Finally, if all else fails, reset the Bluetooth preferences
- Delete the following file (macOS will recreate it): /Library/Preferences/com.apple.Bluetooth.plist
- You’ll need to restart your Mac after doing this.
