You are using utility in the economic sense and not in the decision theorethic sense. If you frame it as "duty" vs "play" it becomes way more understandable.
A utility that you explicitly calculate on a paper can feel like an outside force that forces you to do something. Something that you have internalised as part of your soul and who you are is more just self-expression. While the concept of utility has been used to refer to both it only really ablies to the latter (for example when you turn preferences into ordinal numerical values). A agent not seeing that work has utility isn't in any way contradictory or paradoxical. If you keep your concept more stringent there is a step from going from dollar production into utility. If dollar production isn't the main utlity component then it is not surprising that there is a disconnect with them. This might have the same structure as the question of "free will" as you do not feel that it is your person doing the activity when it is your "employee" doing it as part of your job duties, that is in a sense you are doing "unvoluntary work" (while simultaneusly thinking that if you didn't like your job you would quit, in a sense also believing in voluntary working). It is easier to stop play if you feel like it but doing a similiar decision not to work today as you don't feel like it is a more responcibility calling enterpreneour level decision that can require doing things that might be in conflict with work ethics (or it calls in a more holistic "employee thriving" advanced management theory). It is somewhat popular to hold a stance that you need to work even if you some particular day you don't feel like it.
There is also a well known effect where two groups were given a puzzle and one group was given monetary rewards for completing it and the other wasn't. When afterwards they were given free access to the puzzle those that were not rewarded engaged with it and those that were rewarded did not. I believe the associated theory is about how explcit external rewards destroy intrinsic motivation. It could also be termed how a job were you normally get 10$ for doing you now get 0$ is clearly not worth the effort, the rewarded people tended to evalaute the gain by monetary terms.
You might be doing a somewhat reverse process. Because it generates money it can't be fun because work by definition isn't play.
I recently encountered something that is, in my opinion, one of the most absurd failure modes of the human brain. I first encountered this after introspection on useful things that I enjoy doing, such as programming and writing. I noticed that my enjoyment of the activity doesn't seem to help much when it comes to motivation for earning income. This was not boredom from too much programming, as it did not affect my interest in personal projects. What it seemed to be, was the brain categorizing activities into "work" and "fun" boxes. On one memorable occasion, after taking a break due to being exhausted with work, I entertained myself, by programming some more, this time on a hobby personal project (as a freelancer, I pick the projects I work on so this is not from being told what to do). Relaxing by doing the exact same thing that made me exhausted in the first place.
The absurdity of this becomes evident when you think about what distinguishes "work" and "fun" in this case, which is added value. Nothing changes about the activity except the addition of more utility, making a "work" strategy always dominate a "fun" strategy, assuming the activity is the same. If you are having fun doing something, handing you some money can't make you worse off. Making an outcome better makes you avoid it. Meaning that the brain is adopting a strategy that has a (side?) effect of minimizing future utility, and it seems like it is utility and not just money here - as anyone who took a class in an area that personally interested them knows, other benefits like grades recreate this effect just as well. This is the reason I think this is among the most absurd biases - I can understand akrasia, wanting the happiness now and hyperbolically discounting what happens later, or biases that make something seem like the best option when it really isn't. But knowingly punishing what brings happiness just because it also benefits you in the future? It's like the discounting curve dips into the negative region. I would really like to learn where is the dividing line between which kinds of added value create this effect and which ones don't (like money obviously does, and immediate enjoyment obviously doesn't). Currently I'm led to believe that the difference is present utility vs. future utility, (as I mentioned above) or final vs. instrumental goals, and please correct me if I'm wrong here.
This is an effect that has been studied in psychology and called the overjustification effect, called that because the leading theory explains it in terms of the brain assuming the motivation comes from the instrumental gain instead of the direct enjoyment, and then reducing the motivation accordingly. This would suggest that the brain has trouble seeing a goal as being both instrumental and final, and for some reason the instrumental side always wins in a conflict. However, its explanation in terms of self-perception bothers me a little, since I find it hard to believe that a recent creation like self-perception can override something as ancient and low-level as enjoyment of final goals. I searched LessWrong for discussions of the overjustification effect, and the ones I found discussed it in the context of self-perception, not decision-making and motivation. It is the latter that I wanted to ask for your thoughts on.