No, it is not odd at all to cut your food using your non-dominant hand (left hand) when using a knife and fork. People develop different habits and techniques when it comes to eating and using utensils. Some right-handed individuals might naturally use their right hand for cutting food and their left hand for holding the fork, while others might do it the other way around.
The dominant hand is typically used for precision tasks that require more dexterity and control, such as writing or using a computer mouse. However, when it comes to eating, the dominant hand isn't always the one used for cutting food, especially if it feels more comfortable or natural to use the non-dominant hand for that particular task.
In many cultures, table manners and utensil usage are taught early in life, and the conventions may vary from one region to another. The most important thing is to be comfortable with your eating habits and use utensils safely and effectively.
Whether you use your left hand for cutting or your right hand, the key is to enjoy your meal and practice proper table manners. As long as your eating habits are not causing any inconvenience or discomfort, there's absolutely nothing odd about it.