The minimum-fort-size conjecture for marginal observances

Let $G$ be a graph. Write $\underline{f}(G)$ for the minimum fort size of $G$, let $\mathrm{MObs}(G;i)$ denote the marginal observance at step $i$, and let $\gamma_P(G)$ denote the power domination number. For a positive integer $k$, write $[k]=\{1,\ldots,k\}$. Minimum-fort-size conjecture. If

$$\underline{f}(G)\geq 4,$$

then

$$\mathrm{MObs}(G;i)\geq 4$$

for all $i\in[\gamma_P(G)]$. This asks whether the relationship between minimum fort size and marginal observances established for smaller minimum fort sizes extends to minimum fort size at least four; its status is not resolved in the source.