Gelling is impacted by recipe, additives, fragrances, molds, and in some cases cannot be avoided by refrigeration. So, if you want to avoid gel altogether, look at all those factors.
High percentage of heat producing ingredients (sugars & liquids that contain sugars, such as alcohol beverages, coconut oil, certain fragrances) can created volcanoes even in the freezer, particularly if it's a large batch in one big mold.
A formula with few heat producing ingredients is less likely to gel, even when not refrigerated, particularly if soaped cool to start with and it's smaller batch or in smaller molds.
Smaller molds, and individual bar molds inhibit gel because there is less volume in the molds to heat up, and the surface area around a smaller mold provides greater cooling with the surrounding air.
If you increase the surfaces open to the air, it will decrease the heat inside the mold. When you leave the soap out on the worktops, are they raised on a rack that provides air to reach the bottom surface of the mold? Or are they flat on the worktop?
Are you able to soap any cooler than you do already? Can you use smaller molds to decrease the volume in the mold that is heating up?