Resonate Stems seemed to have stopped dropping upon completing patrols or from chests in lost sectors and high-value targets and Braytech Schematics don't seem to be dropping either. I was farming Resonant Stems on one character for the Sleeper Simulant quest step where you have to open Rasputins Nodes but once I finished the step and switched characters they no longer dropped. Also, after opening the nine remaining nodes for the quest step, not one of them dropped a Braytech Schematic. This could just me my own shitty RNG for the schematic but the Stems are definitely bugged.