Do you know for sure that your vet checked the back teeth 2 weeks ago? Up until now, has your rabbit been eating her normal amounts of hay? Even though the vet may not have found any health issues at the time, it doesn't mean there may not be a hidden health issue that could be causing this. Where blood tests done, urinalysis, full body xrays of the head and organs, or a dental exam under GA to get a more thorough look at the teeth for hidden dental spurs? If not, then it is possible for there to be an underlying health issue as the cause of the repeated lack of appetite and stasis/gas. And even with all of those diagnostics done, things can still be missed or overlooked. Lack of appetite is often just the most obvious symptom of there being something wrong. It may or may not be a digestive issue that is the cause. Any health problem that causes pain and/or discomfort can cause a rabbit to stop eating, which in turn will lead to digestive problems and stasis. But if you aren't seeing any other signs of a health problem such as neurological symptoms, increased thirst and urination, being picky about food and not eating certain things or not eating in the same amounts, odd changes of behavior, that could point to something being the cause, it very well could be happening due to diet alone. I had a rabbit that repeatedly kept having reoccurring stasis and digestive upset, until I figured out it was the pellets causing it. Once I eliminated those from his diet(as he couldn't tolerate even the smallest amount) he never had a bout with stasis again.
What you are feeding is usually perfectly normal for a rabbits diet, but the issue is some rabbits have specific dietary needs. Some may be more sensitive to excess sugars and carbs in the diet, some may be sensitive to a particular veggie, or even a particular type of hay. This can happen from the moment you get your bun, or it can occur later in your rabbits life. A rabbits diet is all about tailoring it to your specific rabbits needs. General dietary guidelines for rabbits are just that, general. Not necessarily suited to all rabbits dietary needs.
Most of my rabbit get pellets, but I tailor the amount they get to how they react to it. If I start to see any mushy poop or small darker poop, I reduce the pellet amount so they eat more hay, which has always resolved the issues for my rabbits. Though many rabbits may do well on a similar diet to what you have your rabbit on, it obviously may be causing issues for your bun, as long as another health issue doesn't end up being the cause. When something specific in the diet is the cause of digestive upset, if you want to prevent it from continuing to occur, you will need to find what exactly in the diet is causing the issue. This is best accomplished by an elimination diet. Grass hay is almost always well tolerated by most rabbits, so starting with that as the base food will get your bun back to feeling better and being healthy, then as you gradually add things back in, if you pay attention to changes in poop and any signs of digestive discomfort, you can usually catch what it is that is causing the issue. That is why you gradually increase, so that if something is causing a problem, you are only starting out with a small amount and can catch the problem before it gets too bad that you need to take your bun to the vet. In my experience, it is almost always too many sugary/starchy treats and/or too many pellets(which contain sugars and carbs) that cause these stasis issues to occur(though a particular veggie or type of hay is always a possibility). Sugars, starches, and carbohydrates slow down a rabbits digestive system, which starts to back up, leads to smaller poop, which then leads to slower emptying of the cecum, which then leads to a bacterial imbalance in the cecum, which leads to gas and digestive upset. So you can see it is a chain reaction of events. Rabbits have a very sensitive digestive system, some more so than others, with specific dietary needs for it to run well and the rabbit to stay healthy and not have digestive issues. Read the articles I shared above. They help explain the issue in more detail.
