It could be, but it's probably not because of the acid specifically. The smallish amount of acid in tomatoes shouldn't have any direct effect on the polymerized oil which makes up the seasoning, and the polymerized oil should prevent the tomatoes from directly touching the reactive bare steel that the wok is likely made of.
Tomatoes do have a high water content which cools down the part of the pan they touch significantly. Combine that with the carbohydrate content of tomatoes and that's a recipe for getting stuck to your pan. Keep in mind: any time you have a food sticking to a seasoned surface, it's sticking to the seasoning, not the metal. When you try to move it, it's going to want to take some of that seasoning with it.
Other things to consider: Are the foods you're cooking wetter, stickier, or sugarier? Are they cooked at a lower temperature? Do they Require more scraping during or after cooking? Use less oil? If you previously did quick and hot stir fries in the pan and are now switching to simmering things, that could definitely loosen up the seasoning, even if it was hot water.
The answer could be as simple as really cranking the heat, making sure you're using enough oil, or using a different pan