1. Open Settings → Devices → Keyboard → Keyboard Shortcuts
2. Scroll down to Navigation, you will find the default for "Switch applications" is Alt+Tab
3. Change "Switch applications" to Super+Tab
4. Change "Switching windows" to Alt+Tab
I can still reproduce the bug after disabling all extensions.
To change Alt+Tab behaviour:
1. Open Settings → Devices → Keyboard → Keyboard Shortcuts
2. Scroll down to Navigation, you will find the default for "Switch applications" is Alt+Tab
3. Change "Switch applications" to Super+Tab
4. Change "Switching windows" to Alt+Tab
I can still reproduce the bug after disabling all extensions.