I never previously used the self damage method, but rather would get killed by enemies during a (solo) mission in order to trigger the mod. This doesn't seem to be working at all anymore, even though the patch notes claim that only death by self inflicted damage should be affected.
My guess is that the mod now only triggers if the sentinel dies and the player character remains alive? However, I have been unable to test this as of yet as this is a much more difficult condition to meet. If this really is intended to be the only way the mod works now, the change appears to render the mod virtually useless, and the farm for certain rare materials *drastically* more tedious and time consuming.
edit2: I've had the chance to do some further testing. For those who would still like to use this mod as a viable way to farm rare mats, it is still easily triggered with the following method: become surrounded by enemies, go into operator form/void mode, allow your sentinel to die (this triggers the mod), *then* return to your warframe and allow yourself to be killed (or I guess kill yourself with lenz) in order to resurrect your sentinel.