Oh ya! It's called hypoglycemic unawareness. Many of us (Type 1's) experience it, especially if keeping BGLs in good control.
I've had this for about
the past year or so, sometimes really bad. I've tested as low as 1.5/27 and not had symptoms. I won't start my car until I've tested for just that reason.
Some will let their BGLs run higher than normal for a time before going back to tight control to get some of that awareness back.
Remember when first diagnosed how a normal of 5.5/100 felt like a hypo?
Funny how it's not all the time, though. Sometimes I'll feel the low and test at a 3.9/70. Always depends on what I've eaten and the activities I'm doing. Sometimes it's just the D throwing you for a loop and keeping you on your toes