I'm pretty new to the healthcare.gov portal, having been covered by employer-sponsored healthcare plans up until mid 2023. I was able to sign my spouse and I up for coverage mid-year this year and that process was surprisingly straightforward. However open enrollment season has begun and I went ahead and started our application for 2024 healthcare coverage.
The pitfall I ran into is that the monthly income estimates you are instructed to enter are misused. As an early retiree couple our income is highly variable from month to month. As I have gotten a feel for the process of optimizing taxes, like many early retirees I take a large capital gains toward the end of the year once other income sources are accounted for and to pay for the next year. This means that for some months we happen to have no actual income, but our yearly income can still be quite high. So this month for the ACA application I put in zeroes for our estimated month income for the month but checked the box that our income is hard to predict. I also filled out our estimated yearly income with those numbers (around $80K to get a good subsidy). I thought that would be sufficient, however the algorithm seems to use only the monthly income as a check for medicaid and so when I submitted I found that I couldn't pick coverage because healthcare.gov suddenly decided I was covered by medicaid. I went to our state medicaid website to look at the income limits for coverage and they were around $40k for our situation - so there's no way we'd be covered since I'm targeting around $80k this year.
I ended up having to resubmit the application and just make up numbers for this month's income that would get us above the $40k if multiplied out by 12 months (still less than the $80k I estimated our yearly income to be) and that seemed to work, but now I probably need to follow up with our state because it automatically forwarded our info there to enroll us in medicaid. Pretty annoying. Anyway I hope this helps others avoid this issue.