Ok, just found your thread regarding this, I'll try installing this latest version and see if it resolves the Perks issue:
// SMXui updated to 19.3.Release1
SMXui - Moved the Perks UI to a separate modlet.
SMXui - Players Window: Adjusted the width of the distance column by 20px.
SMXui - Fixed a small bug in the itemInfoPanel window.
SMXui - Fixed two bugs with the perks/buffs. Thanks Napalm91 for reporting!
SMXui - Fixed a layering issue in the books window.
Both NexusMods and GitHub are now updated with the new versions.
Tried the version from GitHub but still kicks the NullException Error when attempting to access Perks Menu: // SMXui updated to 19.3.Release1