Yesterday, I downloaded a launcher from PlayStore basically an Action Launcher 3. This can be downloaded from PlayStore for free but with limited settings. However if you want full version get it here.
Note: Please support developer if you’ve money to pay for full version. If you don’t have money, download it from there.
Now, in LeEco Le 1s/Max/Le2/Le Max. I downloaded launcher and opened it and set it up. Now when I press home button boom I’m back to default Launcher by LeEco.
So, I did some testing and figured it out why it was happening. And at last fixed it.
All you have to do is go to Settings —> App Management —> Default Apps (It is located in bottom tab in the centre) —-> Launcher —-> Action Launcher 3 (Or any launcher you downloaded on your phone)
Now, your phone will always use Action Launcher 3 as default.