In your initial EU1 application, one of the question is that on what basis you intend to live in Ireland. You would have selected work or study or self-sufficiency. So either you accidentally selected self-sufficiency at that time, or maybe you selected the correct one but INIS recorded it incorrectly in their system.
Either way, you just have to explain to them that the EU citizen is working and you are here based on her working full time. Give them a copy of P60 / P21 for the last 5 years and employment letters / contracts if you have them.
I would not have expected that they were asking for a health insurance covering 10 days.
But just to answer your question in your followup post - they do have the power to ask for the BOTH the applicant AND the EU citizen's health insurance details, IF your application is based on self-sufficiency. (This means even if you work full time, as long as your EU spouse exercised her treaty rights based on her-self sufficiency, you still need to hold the insurance at all times).
This is specifically mentioned on the EU1 form:
Where the EU citizen has sufficient resources to maintain themselves and any dependants in the State, while possessing comprehensive sickness insurance in respect of themselves, their spouse, and any dependants