The paper by David Shlivko and Paul J. Steinhardt examines the observational constraints on time-varying dark energy, specifically quintessence models. The authors critique the common practice of presenting these constraints on a $w_0$-$w_a$ plot, which assumes a specific equation of state for dark energy. Recent observations suggest a sector of the $w_0$-$w_a$ plane where $w_0 > -1$ and $w_0 + w_a < -1$, indicating a transition from violating the null energy condition (NEC) at large redshifts to obeying it at small redshifts. However, the authors argue that this impression is misleading because simple quintessence models satisfying the NEC for all redshifts can still predict an observational preference for the same sector. The paper also highlights that quintessence models that best fit observational data can have a significantly different value for the dark energy equation of state at present compared to the best-fit value of $w_0$ obtained using the $w_0$-$w_a$ parameterization. Additionally, the analysis reveals an approximate degeneracy in the $w_0$-$w_a$ parameterization, which explains the eccentricity and orientation of the likelihood contours in recent observational studies. The authors use a mapping technique to predict where observational preferences should fall on the $w_0$-$w_a$ plane for various quintessence models driven by a scalar field. They consider models with exponential potentials, hilltop potentials, and plateau potentials, and show that these models are mapped onto the same sector of the $w_0$-$w_a$ plane as observations currently prefer, even though they do not violate the NEC. This finding suggests that the observational preference for a region with $w_0 + w_a < -1$ does not necessarily imply NEC violation at any redshift. The paper discusses the implications of these findings for interpreting observational likelihood contours, the consistency of dark energy models with theoretical frameworks like supergravity and string theory, and the nature of dark energy's behavior over time. The authors conclude that including combinations of $(w_0, w_a)$ satisfying $w_0 + w_a < -1$ in observational analyses is crucial to avoid excluding well-motivated models of thawing quintessence.The paper by David Shlivko and Paul J. Steinhardt examines the observational constraints on time-varying dark energy, specifically quintessence models. The authors critique the common practice of presenting these constraints on a $w_0$-$w_a$ plot, which assumes a specific equation of state for dark energy. Recent observations suggest a sector of the $w_0$-$w_a$ plane where $w_0 > -1$ and $w_0 + w_a < -1$, indicating a transition from violating the null energy condition (NEC) at large redshifts to obeying it at small redshifts. However, the authors argue that this impression is misleading because simple quintessence models satisfying the NEC for all redshifts can still predict an observational preference for the same sector. The paper also highlights that quintessence models that best fit observational data can have a significantly different value for the dark energy equation of state at present compared to the best-fit value of $w_0$ obtained using the $w_0$-$w_a$ parameterization. Additionally, the analysis reveals an approximate degeneracy in the $w_0$-$w_a$ parameterization, which explains the eccentricity and orientation of the likelihood contours in recent observational studies. The authors use a mapping technique to predict where observational preferences should fall on the $w_0$-$w_a$ plane for various quintessence models driven by a scalar field. They consider models with exponential potentials, hilltop potentials, and plateau potentials, and show that these models are mapped onto the same sector of the $w_0$-$w_a$ plane as observations currently prefer, even though they do not violate the NEC. This finding suggests that the observational preference for a region with $w_0 + w_a < -1$ does not necessarily imply NEC violation at any redshift. The paper discusses the implications of these findings for interpreting observational likelihood contours, the consistency of dark energy models with theoretical frameworks like supergravity and string theory, and the nature of dark energy's behavior over time. The authors conclude that including combinations of $(w_0, w_a)$ satisfying $w_0 + w_a < -1$ in observational analyses is crucial to avoid excluding well-motivated models of thawing quintessence.