One of the issues that i've observed with OpenAI, is that things the model got wrong a week ago it suddenly starts getting right but other examples that are not

One of the issues that i've observed with OpenAI, is that things the model got wrong a week ago it suddenly starts getting right but other examples that are not exactly the same question but very similar or another example of the same thing it gets wrong, then a few weeks passes and it gets this right. My conclusion is that they are using the data from users to improve or some other prompt injection tricks. So the comparision is not even fair.