I just assumed that mind, itself, was the culprit there, & that Higher Mind was something other, unlike lower mind. Now I realize that they are — or can be — simply one.
I have experienced that, too. I suspect “lower mind” is mostly a shorthand way of talking about the experience of living with higher mind shackled by culture and habit. Experiencing higher mind is less a matter of grasping at something higher as it is a matter of letting go of old habits.