Hi,
How old is your CF child?
Yes, Nathan use to get fevers like that. I have chosen to home school him for many reasons, this being one of them. For about 2 years while home-schooling we did a program where the kids went to school on Fridays with other home-schooled kids and every Friday, without fail, Nathan would come home exhausted and running a fever as high as 102.5. We would go home, he would rest, go to bed early, sleep in on Saturday, do next to nothing on Saturday, and would be fine come Sunday morning, the rest of the week he would be just fine and then Friday would come and we would do it all over again. He wasn't enjoying going to Friday school so he quite and was fine.
However, now we are running fevers beginning sometime after dinner 4 to 5 times a week, by morning he is fine. Though I should tell you that he did grow mycobacterium abscessus in Oct and if he truly has this bug it is likely the source of the fevers now. He has to grow it 2 more times before he officially is diagnosed with the NTMA (Non-Turbuculosis Mycobacterium Abscessus) and are currently waiting on the results of his Dec culture and Jan culture.
I would definetly report it to your CF center and ask if they have done cultures for mycobacterium specifically. I know that there is a high rate of the NTM's being cultured lately then in the past and you might want to rule that out as being the cause. But know that you techniqually have to have 3 cultures at least a month apart before you can officially say that it is the source of the fevers. Plus, it is a bug you really do not want to have and is very good if it isn't that.
I am not sure that you can say that fevers are a typical CF thing or not, but I have a friend who has a daughter with CF who also ran "unexplained" fevers as well.
Not sure I am helping or making things worse for you. Check with your doc for sure.