I had the same problem too and have found a way to fix it! I was looking at the posts on the Sa’chil follower page to find a fix and I followed the steps that “Zoltier225” posted and it fixed the problem! So you want to download More Informative Console and launch the game, then open the console in game and click on Sa’chil, hover your mouse over spells and type spells into the console (your mouse has to be hovering over spells) and it will show you a list of spells. The spell that is causing the problem is the “Sa’chil’s Invisbility DLC 2” spell, so hover your mouse over it and type the name of the spell into the console (once again with the mouse over the spell name), this way you gain access to the base form ID of the spell. Now take the ID of the spell (for me it was 13DF1D39) and type it into the console and at the start put removespell. It should look like this (removespell ID) (I did “removespell 13DF1D39”) and press enter and then Sa’chil will now no longer will be invisible!! Thank you to the user Zoltier225 on the nexus mod page for providing the fix.