You're my hero for still hanging in there after all this crap you've had to deal with since nougat.The issue is Magisk, not BD or this kernel. Magisk v12 loses root now and then, and further the overlay files the SkyHigh Magisk module lays down are not necessarily compatible with BD (Samsung played a very bad trick on S6 users). All that will surely drive one nuts. Magisk V12 also cannot pass SafetyNet without dramatic acrobatics. That is why SuperSU let's you succeed. SuperSU, however, does not have the kind of module abilities and hiding that Magisk has. We are just caught in a bit of transition.
As well, so all know, the latest firmware has a dramatic number of better memory leak fixes, so those who kept trying to fix that with kernel tweaks (or otherwise thinking somehow the kernel was leaking) will be thrilled. That's likely the end of BD ROM unless the author one day sends the base so possibly I can update it.
Next update to this kernel roots with v13 Magisk, which we just got dramatically close to release today. We are literally days away now. Soon thereafter I'll update this kernel.
Working with Magisk has not need easy, so I definitely applaud your efforts and feel your pain. With that said, I am running my latest TDHJR ROM (not yet released for the same reasons -- waiting for release of v13 Magisk) with Magisk v13 beta (latest, dropped just today) and it is flawless so far.
I will update everyone very soon.
Agreed on the flawlessness of the new magisk beta, the only issue I've run into is magisk not setting proper permissions for boot scripts
Also, yes the firmware news is a huge relief lol