I can confirm thar im runing Lucky patcher in Android 8 and not having problems with safetynet.

Maybe u were already rooted with super su or anything else before rooting with magisk and there are traces of this in your system. 

This is what worked for me. 

I reinstalled my Phone to factory settings using a service image. The image that u flash through stock recovery. 

Configured my Phone, Gmail account, bassic settings etc. 

Unlock bootloader 

Flash twrp 

Backup off all partitions (Just in case) 

Flash magisk zip

Install magisk manager 

Enable magisk su, magisk hide for the apps that require it. In my case is Just pokémon go. 

If i check safety net Status on magisk it says passed. 

I can run pokemon go no problems

I can find and download Netflix from play store. 

I mention this last two things because i have read that if u have safety net problems, you cant play pokemon go (i had this problem) and you cant download Netflix from playtore (not sure about this one since i dont use Netflix. 

Btw another great feature of Lucky patcher. If under magisk you have problems getting rid of all the bloat apps Google and ur device manufacturer put in the Phone, Just uninstall this vía Lucky patcher, (in my case titanium Backup and root uninstaller couldnt do that) 

This was on a p10 lite runing android 8 of course the process in ur Phone May be different