R2L2D circuit becomes a chaotic circuit at certain frequencies and amplitudes. In the present study, new and strange phenomena, which is encountered in a newly-developed circuit, namely R2L2D circuit is reported. This new phenomena, which we called as the "sweep up/down effect" has been observed when the successive dynamic responses of the circuit have been explored by only adjusting the peak-to-peak amplitudes Vpp at a constant feeding frequency, namely integral - 65 kHz. In one of our recent paper , this new circuit has been explored for a wide feeding amplitude and frequency regimes, whereas this effect has not been recognized at that time due to the lack of sensitivity. However, the detailed observations prove that the sweep up/down effect governs the identification of the dynamics in terms of periodic and chaotic regimes. Thus it gives a kind of uncertainty region at the threshold of the regimes depending on the feeding voltage increase or decrease. Besides, for a certain system parameter, i.e. Vpp, the chaotic and periodic region co-exists phenomenologically. This effect becomes vital for the synchronization and encryption studies in the sense that the decrease/increase in amplitude certainly yield to regular or chaotic behavior in the output. In addition, the transitions from regular regime to the chaotic one or vice-verse takes place without any period doubling procedure apart from the traditional observations.