I agree-- I would suspect a mixing issue more than a temperature issue.
Are you using a stick blender? I find that a lot of times, the SB will give me a
"false trace" that when swirled a bit, disappears. My remedy is to SB in short bursts (3-5 seconds or so), and stir for about 10-12 seconds. Then pulse again, and stir. Keep repeating until you reach at least a medium trace.
I usually soap around 109F... as high as 113, and as low as about 90. I know many on here do RT soaping with great results. Given the range of temps that we all have success with, I thinking mixing is more to blame for most separation issues.