They have always been in there, it was never a problem until one day they vansihed from Premier Pro, I can use them fine in the Lumetri Color effect. but thats a pain.
There are two places built into their system where users can place LUTs for different tab usage within Lumetri, and have the LUTs be seen by the apps ... all three ... Premiere, AfterEffects, and MediaEncoder.
Staffer @Kevin-Monahan posted a good FAQ on the forum about this ...