Considering the Co(hmba)3[CoBr4] system, we find a decrease in its glass transition temperature from a pristine value of 16 °C to -15 °C for the highest water content studied, which corresponds to nine water molecules per bridging Co atom, where bridging-Co refers to Co atoms bonded to hmba linkers. Notably, a significant initial decrease followed by stabilization is observed for both Tm and Tg. Specifically, Tm and Tg reach a constant value when around three to four water molecules per bridging-Co have been added. Interestingly, this is equivalent to the ratio of bridging-Co to hmba in the system. Thus, at the water concentration of Tg-convergence, one water molecule per hmba linker is present. Considering the chemical environment of the percolating network, i.e., Co-nodes connected by bidentate hmba-linkers through Co-O coordination bonds, the monodentate water species thus appear to replace the bridging carbonyl oxygens around the Co-centers. This leads to a fully depolymerized network of Co atoms surrounded by a distribution of hmba-linkers and water molecules, while the [CoBr4] 2--tetrahedra would remain intact. As such, this behavior is equivalent to water-based modifier addition in the HCNG system, which, to our knowledge, has not previously been reported for hybrid glasses.