I think the most likely explanation is that ambient lighting conditions in the room where OP was sitting, as described in the original question, might not have been bright enough to saturate the rods. Under mesopic conditions, both rods and cones are active. Hence your statement that
...since the light from CRT mentioned in the question pointed to by the first link above is quite above the photopic threshold.
may not hold. Since rods indeed have quicker responses, the periphery may be more sensitive to the flickering of a CRT or light bulb.
Note, however, that cones have flicker fusion frequencies of up to 90 Hz (reviewed by Perz, 2010), and CRT screens and light bulbs flicker at frequencies following the mains (50 or 60 Hz). Hence, cones may still be able to pick up the flickering. Since OP reports on an anecdote, experimental conditions may have been suboptimal and their report might have been unreliable. So we cannot exclude OP was using photopic vision, regardless their report.
- Perz, Master's thesis, Eindhoven University