A spoonful of oil and a spoonful of vegan spread may both look like fat, but they are not necessarily equivalent ingredients. Spreads can contain substantial water, and a solid baking block behaves differently during mixing.
If a recipe asks you to cream softened fat with sugar, its method depends partly on that texture. Pouring in oil changes the process. If the recipe is designed for oil, replacing it with a cold block creates another problem.
Choose the specified product type where possible and check that it is suitable for baking. A tub intended for spreading on toast may not perform like a block made for pastry.
When experimenting, change one thing at a time and write it down. A batch with a new fat, different flour, less sugar, and another pan size gives you very little chance of identifying which change caused the result.
Further reading: King Arthur Baking: baking without dairy.